Questions
Construct the 92% confidence interval for mean of following data by assuming that the data follow...

Construct the 92% confidence interval for mean of following data by assuming that the data follow normal distribution. You have to use 92% Z value.

132, 135, 149, 133, 119, 121, 128, 132, 119, 110, 118, 137, 140, 139, 107, 116, 122, 124, 115, 103

In: Statistics and Probability

Thirty professors took an intensive teacher-training class before the Fall ’14 semester began and they were...

Thirty professors took an intensive teacher-training class before the Fall ’14 semester began and they were paired with professors teaching the same courses who did not take the intensive training class. Course evaluations were compared at the end of the semester, and the mean advantage for those who took the course compared to their matched counterparts was 1 point on ratings of the question “The instructor is an excellent teacher.” The standard deviation of this difference was 2.5. Do teacher training classes improve teaching evaluations? Use a 1% significance level. Show your work for all 4 steps in hypothesis testing. Be sure to include diagrams and to determine and interpret the p-value for your test-statistic. State in words the conclusion you reach from the hypothesis test suggests about the answer to the italicized question.

In: Statistics and Probability

Cholesterol levels for a group of women aged 50-59 follow an approximately normal distribution with mean...

Cholesterol levels for a group of women aged 50-59 follow an approximately normal distribution with mean 216.57 milligrams per deciliter (mg/dl). Medical guidelines state that women with cholesterol levels above 240 mg/dl are considered to have high cholesterol and about 29.6% of women fall into this category.

1. What is the Z-score that corresponds to the top 29.6% (or the 70.4-th percentile) of the standard normal distribution? Round your answer to three decimal places.

2. Find the standard deviation of the distribution in the situation stated above. Round your answer to 1 decimal place.

In: Statistics and Probability

If we increase our food intake, we generally gain weight. Nutrition scientists can calculate the amount...

If we increase our food intake, we generally gain weight. Nutrition scientists can calculate the amount of weight gain that would be associated with a given increase in calories. In one study, 16 nonobese adults, aged 25 to 36 years, were fed 1000 calories per day in excess of the calories needed to maintain a stable body weight. The subjects maintained this diet for 8 weeks, so they consumed a total of 56,000 extra calories. According to theory, 3500 extra calories will translate into a weight gain of 1 pound. Therefore, we expect each of these subjects to gain 56,000/3500 = 16 pounds (lb). Here are the weights before and after the 8-week period, expressed in kilograms (kg).

Subject 1 2 3 4 5 6 7 8
Weight before 55.7 54.9 59.6 62.3 74.2 75.6 70.7 53.3
Weight after 61.7 58.7 66.1 66.2 79.1 82.4 74.3 59.3
Subject 9 10 11 12 13 14 15 16
Weight before 73.3 63.4 68.1 73.7 91.7 55.9 61.7 57.8
Weight after 79.1 65.9 73.3 76.8 93.2 63.0 68.3 60.2

(a) For each subject, subtract the weight before from the weight after to determine the weight change in kg.

Subject 1        kg
Subject 2   kg
Subject 3   kg
Subject 4   kg
Subject 5   kg
Subject 6   kg
Subject 7   kg
Subject 8   kg
Subject 9   kg
Subject 10   kg
Subject 11   kg
Subject 12   kg
Subject 13   kg
Subject 14   kg
Subject 15   kg
Subject 16   kg



(b) Find the mean and the standard deviation for the weight change. (Round your answers to four decimal places.)

xkg =   kg
skg =   kg



(c) Calculate the standard error se and the margin of error me for 95% confidence. (Round your answers to four decimal places.)

se =
me =



Report the 95% confidence interval for weight change in a sentence that explains the meaning of the 95%. (Round your answers to four decimal places.)

Based on a method that gives correct results 95% of the time, the mean weight change is   kg to   kg.


(d) Convert the mean weight gain and standard deviation in kilograms to pounds. Because there are 2.2 kg per pound, multiply the value in kilograms by 2.2 to obtain pounds. (Round your answer to four decimal places.)

xlb = lb
slb = lb



Do the same for the confidence interval. (Round your answers to four decimal places.)

  ,

lb

(e) Test the null hypothesis that the mean weight gain is 16 lb. (Let

α = 0.05.)



Specify the null hypothesis.

H0: μ > 16

H0: μ ≠ 16

    

H0: μ ≥ 16

H0: μ = 16

H0: μ ≤ 16


Specify the alternate hypothesis.

Ha: μ = 16

Ha: μ < 16

    

Ha: μ ≥ 16

Ha: μ ≠ 16

Ha: μ > 16


Carry out the test. (Round your answer for t to three decimal places.)

t =



Give the degrees of freedom.


Give the P-value. (Round your answer to four decimal places.)

In: Statistics and Probability

1. Chi-squared :      X Y Row Marginals A: 60, 30, 90 B: 18, 40, 58 Column...

1. Chi-squared :

     X Y Row Marginals

A: 60, 30, 90

B: 18, 40, 58

Column Marginal: 78, 70, 140

In: Statistics and Probability

Ten individuals have their systolic blood pressures measured while they are in the dentist’s waiting room...

Ten individuals have their systolic blood pressures measured while they are in the dentist’s waiting room and again an hour after the conclusion of the visit to the dentist. The data are as follow: (5 Points).

B.P before

132

135

149

133

119

121

128

132

119

110

B.P after

118

137

140

139

107

116

122

124

115

103

Write a four step procedure to conduct test of hypothesis for the above data

Test the hypothesis at 3% level of significance whether mean difference of the blood pressure before and after visit is zero or not.

In: Statistics and Probability

Jensen Tire & Auto is in the process of deciding whether to purchase a maintenance contract...

Jensen Tire & Auto is in the process of deciding whether to purchase a maintenance contract for its new computer wheel alignment and balancing machine. Managers feel that maintenance expense should be related to usage, and they collected the following information on weekly usage (hours) and annual maintenance expense (in hundreds of dollars).

Weekly Usage
(hours)
Annual
Maintenance Expense
15 20
12 25
22 33
30 40
34 50
19 34
26 36
33 42
42 55
40 43

Develop the estimated regression equation that relates annual maintenance expense (in hundreds of dollars) to weekly usage hours (to 3 decimals).
Expense = + Weekly Usage

Test the significance of the relationship in part (a) at a .05 level of significance.

Compute the value of the F test statistic (to 2 decimals).


The p value is - Select your answer -less than .01between .01 and .025between .025 and .05between .05 and .10greater than .10Item 4

What is your conclusion?
- Select your answer -Conclude that there is a significant relationship between expense and weekly usageDo not conclude that there is a significant relationship between expense and weekly usageItem 5

Jensen expects the new machine to be used 30 hours per week. What is the expected annual maintenance expense in hundreds of dollars (to 2 decimals)?


Develop a 95% prediction interval for the company's annual maintenance expense for this machine (to 2 decimals).
( , )

If the maintenance contract costs $3000 per year, would you recommend purchasing the contract for the new machine in part (c)?

In: Statistics and Probability

1. How many sources are you required to write annotations about for your Annotated Bibliography? 2....

1. How many sources are you required to write annotations about for your Annotated Bibliography?

2. If you have more sources than the required amount for your Annotated Bibliography, then are you supposed to write more annotations and include them in your Annotated Bibliography?

3. How many academic peer reviewed sources are you required to include in your Annotated Bibliography?

4. In addition to the bibliographic information about your sources, what are the 3 different aspects you are required to include in your 3-part annotations for each of your sources?

5.In your own words, what is the purpose of a citation?

6. What is the additional value/purpose of an Annotated Bibliography? Why do professors required students to write them?

7. Provide a basic set of criteria for evaluating information sources, and a basic set of criteria for evaluating the credibility of an author or publisher.

8. And next week, you will need to post information about at least THREE of your sources, so make sure to do lots of research so you will be prepared! plzz help

In: Statistics and Probability

Before they can be marketed, all new medical devices must be approved by the Food and...

  1. Before they can be marketed, all new medical devices must be approved by the Food and Drug Administration (FDA). A new device has a protective cover which needs to be removed easily. A similar device, already on the market, has a cover that requires an average force of 8 pounds to remove. The laboratory test data on a random sample of 9 of the new device indicates the following removal forces:

        6.3, 8.4, 7.8, 6.4, 5.4, 8.0, 7.0, 6.2, 7.5

    Assume that the removal force has a normal distribution with a standard deviation σ =1.2 pounds. Does the data support the conclusion that the new device requires an average removal force less than 8 pounds? When making decision, let the probability of making a type I error be no more than 0.10.

    The correct set of null & alternative hypotheses are:

    a.

    Ho: μ > 8     Ha: μ ≤ 8

    b.

    Ho: μ < 8     Ha: μ ≥ 8

    c.

    Ho: μ ≤ 8     Ha: μ = 8

    d.

    Ho: μ ≥ 8     Ha: μ < 8

3 points   

QUESTION 9

  1. The significance level of the test is:

    a.

    0.01

    b.

    0.02

    c.

    0.05

    d.

    0.10

2 points   

QUESTION 10

  1. The test-statistic appropriate for this test is distributed as a

    a.

    Z random variable.

    b.

    t random variable.

    c.

    Z random variable, but can be approximated as a t.

    d.

    t random variable, but can be approximated as a Z.

3 points   

QUESTION 11

  1. The computed value of test statistic equals

    a.

    -2.5

    b.

    -3.0

    c.

    2.3

    d.

    1.80

3 points   

QUESTION 12

  1. The critical value of the test is:

    a.

    -2.326

    b.

    -2.576

    c.

    1.645

    d.

    -1.282

2 points   

QUESTION 13

  1. The decision is that

    a.

    the alternative hypothesis is rejected. The average removal force is greater than 8 lbs.

    b.

    the null hypothesis is rejected. The average removal force is less than 8 lbs.

    c.

    Not enough information is given to answer this question.

    d.

    the alternative hypothesis is accepted. The average removal force is greater than 8 lbs.

3 points   

QUESTION 14

  1. The p-value of the test is:

    a.

    0.0359

    b.

    0.0107

    c.

    0.0013

    d.

    0.0062

3 points   

QUESTION 15

  1. Using p-value criterion, the decision is:

    a.

    Reject H0.

    b.

    Fail to reject H0.

    c.

    Reject Ha.

    d.

    Fail to reject Ha.

In: Statistics and Probability

2. Behavior of wearing seat belt has two categories: Most Times or Always and Rarely or...

2. Behavior of wearing seat belt has two categories: Most Times or Always and Rarely or Never. Overall Grades for Undergraduate Degree has three categories: A or B, C, and D or F. In a group of 1534 students with grades A or B, 1354 students wear seat belts Most time or Always. In a group of 553 students with grade C, 428 students wear seat belts Most Time or Always. In a group of 105 students with grades D or F, 65 wear seat belts Most Time or Always. Conduct a test the hypothesis at 5% level of significance that Wearing seat belts and Grades at Undergraduate degree are independent or not. Show all four steps.

In: Statistics and Probability

A pizza restaurant offers various kinds of toppings for you to choose from: (each topping can...

A pizza restaurant offers various kinds of toppings for you to choose from: (each topping can only be chosen at most once)

Meat: Turkey, Bacon, Pepperoni, Chicken, Meatballs

Vegetables and Fruits: Black Olives, Pineapple, Mushroom, Onion

Cheese: Mozzarella, Parmesan

a) How many pizzas with different toppings could you order if you can choose any number of the toppings available to include, including no toppings.

b) How many different pizzas could you order if you must include at least two different toppings from those available?

c) How many different pizzas could you order if you could pick any choices of meat (including none), exactly one choice of vegetables and fruits and exactly one choice of the cheese as your toppings?

In: Statistics and Probability

A medical researcher compares the pulse rates of smokers and nonsmokers. A sample of 71 smokers...

A medical researcher compares the pulse rates of smokers and nonsmokers. A sample of 71 smokers had a mean pulse rate of 81. A sample of 86 nonsmokers had a mean pulse rate of 77. Assume the standard deviation of the pulse rates is known to be 7 for smokers and 7 for non- smokers. Using these results, conduct a hypothesis test of the conjecture that the true mean pulse rate for smokers is different from the true mean pulse rate for nonsmokers at 0.05 level of significance

In: Statistics and Probability

Ten different families are tested for the number of gallons of water a day they use...

Ten different families are tested for the number of gallons of water a day they use before and after viewing a conservation video. At the 0.05 significance level, test the claim that the mean is the same before and after the viewing.

  • List the null and alternative hypothesis,
  • the critical value,
  • the test statistic with and sd.
  • Draw the graph and label the test statistic, critical value and rejection regions.
  • Reject or fail to reject?
  • State the conclusion

Before

33

33

38

33

35

35

40

40

40

31

After

34

28

25

28

35

33

31

28

35

33

In: Statistics and Probability

Hi I need the solution in details (show your work) Monthly sales at a coffee shop...

Hi I need the solution in details (show your work) Monthly sales at a coffee shop have been analyzed. The seasonal index values are Month Index Jan 1.38 Feb 1.42 Mar 1.35 Apr 1.03 May 0.99 June 0.62 July 0.51 Aug 0.58 Sept 0.82 Oct 0.82 Nov 0.92 Dec 1.56 and the trend line is 74123 + 26.9(t). Assume there is no cyclical component and forecast sales for year 8 (months 97 - 108).

In: Statistics and Probability

A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of...

A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 226 students using Method 1 produces a testing average of 69.8. A sample of 191 students using Method 2 produces a testing average of 81.5. Assume that the population standard deviation for Method 1 is 11, while the population standard deviation for Method 2 is 16.55. Determine the 99% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2. Step 1 of 3: Find the point estimate for the true difference between the population means. A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 226 students using Method 1 produces a testing average of 69.8. A sample of 191 students using Method 2 produces a testing average of 81.5. Assume that the population standard deviation for Method 1 is 11, while the population standard deviation for Method 2 is 16.55. Determine the 99% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2.

Step 2 of 3: Calculate the margin of error of a confidence interval for the difference between the two population means. Round your answer to six decimal places. A researcher compares the effectiveness of two different instructional methods for teaching physiology. A sample of 226 students using Method 1 produces a testing average of 69.8. A sample of 191 students using Method 2 produces a testing average of 81.5. Assume that the population standard deviation for Method 1 is 11, while the population standard deviation for Method 2 is 16.55. Determine the 99% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2.

Step 3 of 3: Construct the 99% confidence interval. Round your answers to one decimal place.

In: Statistics and Probability