a.

Which of the following is true?

Group of answer choices

Additional variables can add noise to the model that slightly increases R-squared

All the options are true

You can use multiple independent variables to predict a dependent variable

The R-Squared value is a measure of how good the model is.

b.This term refers to when two predictor variables are highly correlated with each other and so the effect of the variables on the dependent response is questionable.

1. Find the​ (a) mean,​ (b) median,​ (c) mode, and​ (d) midrange for the given sample data.

An experiment was conducted to determine whether a deficiency of carbon dioxide in the soil affects the phenotype of peas. Listed below are the phenotype codes where 1=smooth-yellow​,2=smooth-green​, 3=wrinkled-yellow​, and 4=wrinkled-green.

Do the results make​ sense?

​(a) The mean phenotype code is _____.

2. Statistics are sometimes used to compare or identify authors of different works. The lengths of the first 10 words in a book by Terry are listed with the first 10 words in a book by David. Find the mean and median for each of the two​ samples, then compare the two sets of results.

The mean number of letters per word in​ Terry's book is _____.

3. Refer to the data set of​ times, in​ minutes, required for an airplane to taxi out for​ takeoff, listed below. Find the mean and median. How is it helpful to find the​ mean?

Click the icon for the taxi out takeoff data.

Find the mean and median of the data set using a calculator or similar data analysis technology.

The mean of the data set is _____ minutes.

4. Find the mean of the data summarized in the given frequency distribution. Compare the computed mean to the actual mean of 50.4 miles per hour.

The mean of the frequency distribution is _____ miles per hour.

5.Six different​ second-year medical students at Bellevue Hospital measured the blood pressure of the same person. The systolic readings​ (in mmHg) are listed below. Find the​ range, variance, and standard deviation for the given sample data. If the​ subject's blood pressure remains constant and the medical students correctly apply the same measurement​ technique, what should be the value of the standard​ deviation?

126   126   138   125   137   134

Range= ______ mmHg

A fair die is rolled twice. Let X be the maximum of the two rolls. Find the distribution of X.

Let Y be the minimum of the two rolls. Find the variance of Y.

A researcher would like to examine how the chemical tryptophan, contained in foods such as turkey, can affect mental alertness. A sample of n = 8 college students is obtained, and each student’s performance on a familiar video game (total points earned in the game) is measured before and after eating a traditional Thanksgiving dinner including roast turkey. The following table are the scores for each participant before and after the meal:

Participants: 1,2,3,4,5,6,7,8,

Before Meal (X1): 220,245,215,260,300,280,250,310

After Meal (X2) 210,220,195,265,275,290,220,285

a.For a two-tailed test, what is the null hypothesis using statistical notation?

b. For a two-tailed test, what is the alternative hypothesis using statistical notation?  

c. What is the sum of the difference scores (D)?

d. What is the value of MD?

e. What is the value for Sum of Squares for the difference scores (SSD)?

f. What is the sample variance for the difference scores (sD 2 )?

g. What is estimated standard error (sMD)?

h. For a two-tailed test with α = .05, what is the value/s for tcrit?

i. What is the value for tobt?  

j. Do these data indicate a significant difference between the treatments at the .05 level of significance? NOTE: simply writing that the effect is significant (e.g., only writing “reject the null”) without showing any work/calculations in parts a-e will result in point zero points.

k. Compute estimated Cohen’s d to measure the size of the treatment effect.

Find the critical value or values of ² based on the given information.

H₀:  = 8.0
n = 10
= 0.01

Here is the data for our experiment.

The data are the SMUT scores of the students in each group. Notice that we have a different number (n) for the lecture group. This is to show you that we can have uneven sets of data for ANOVA. Note: If we were doing a real study, we would have larger n’s. Enter the data into the Excel spread sheet, SPSS or your calculator

This assignment is part of my ANOVA Exercise, I will please need help in completing it.

Thanks

1. Use the data in CEOSAL for this exercise. Consider an equation to explain salaries of CEOs in terms of annual firm sales, return on equity (roe, in percentage form), and return on the firm’s stock (ros, in percentage form). Answer questions after estimating the equation

log(salary)=β0+β1log(sales)+β2roe+β3ros+u.

1. (3 points) By what percentage is salary predicted to increase if ros increases by 50 points? Does ros have a practically large effect on salary?
2. (3 points) Test the null hypothesis that ros has no effect on salary against the alternative that ros has a positive effect. Carry out the test at the 10% significance level.
3. (2 points) Would you include ros in a final model explaining CEO compensation in terms of firm performance? Explain.

Consider the following data drawn independently from normally distributed populations: (You may find it useful to reference the appropriate table: z table or t table)

a. Construct the 95% confidence interval for the difference between the population means. (Negative values should be indicated by a minus sign. Round all intermediate calculations to at least 4 decimal places and final answers to 2 decimal places.)

Confidence internval is _____ to ____.

Consider the following competing hypotheses and accompanying sample data drawn independently from normally distributed populations. (You may find it useful to reference the appropriate table: z table or t table)

H₀: μ₁ − μ₂ = 0
H_A: μ₁ − μ₂ ≠ 0

a-1. Calculate the value of the test statistic. (Negative values should be indicated by a minus sign. Round all intermediate calculations to at least 4 decimal places and final answer to 2 decimal places.)
  

Test statistic:

Researchers at The Wharton School of Business have found that men and women shop for different reasons. While women enjoy the shopping experience, men are on a mission to get the job done. Men do not shop as frequently, but when they do, they make big purchases like expensive electronics. The accompanying table shows the amount spent (in $) over the weekend by 40 men and 60 women at a local mall. The Excel file is also provided. (You may find it useful to reference the appropriate table: z table or t table)

Click here for the Excel Data File

Let µ₁ represent the population mean amount spent by men and µ₂ represent the population mean amount spent by women.

a. Specify the competing hypotheses that determine if the mean amount spent by men is more than that by women.

• H₀: μ₁ − μ₂ = 0; H_A: μ₁ − μ₂ ≠ 0

• H₀: μ₁ − μ₂ ≥ 0; H_A: μ₁ − μ₂ < 0

• H₀: μ₁ − μ₂ ≤ 0; H_A: μ₁ − μ₂ > 0

b. Calculate the value of the test statistic. Assume that the population variances are unknown but equal. (Round intermediate calculations to at least 4 decimal places and final answer to 2 decimal places.)

test statistic:

Consider the following excerpts from a New York Times article:
Despite its early promise … Restoration has had trouble becoming a mass-market
player … What went wrong? High on its own buzz, the company expanded at breakneck
speed, more than doubling the number of stores, to 94, in the year and a half after the
stock offering … Company managers agree, for example, that Restoration’s original
inventory system, which called for all furniture to be kept at stores instead of a central
warehouse, was a disaster.
Let’s look at one Restoration Hardware product, a leather chair. Average weekly sales
of this chair in each store is normally distributed with mean 1.25 units and standard
deviation 0.5 units. The replenishment lead time is 12 weeks. There is information
system in place.
 If each store holds its own inventory, then what is the company’s average
inventory if the company policy is to target a 99.25 percent in-stock probability?
 Suppose Restoration Hardware builds a central warehouse to serve the 94
stores. The lead time from the supplier to the central warehouse is 12 weeks.
The lead time from the central warehouse to each store is one week. Suppose
the warehouse operates with a 99 percent in-stock probability, but the stores
maintain a 99.25 percent in-stock probability. If only inventory at the retail
stores is considered, what is Restoration’s average inventory?

A popular theory is that presidential candidates have an advantage if they are taller than their main opponents. Listed are heights​ (in centimeters) of randomly selected presidents along with the heights of their main opponents. Complete parts​ (a) and​ (b) below. Height left parenthesis cm right parenthesis of President Height (cm) of President 189 189 174 174 181 181 180 180 187 187 166 166 Height left parenthesis cm right parenthesis of Main Opponent Height (cm) of Main Opponent 177 177 189 189 170 170 166 166 180 180 180 180 a. Use the sample data with a 0.05 0.05 significance level to test the claim that for the population of heights for presidents and their main​ opponents, the differences have a mean greater than 0 cm.

A data set about speed dating includes​ "like" ratings of male dates made by the female dates. The summary statistics are

nequals=195195​,

x overbarxequals=7.537.53​,

sequals=1.971.97.

Use a

0.050.05

significance level to test the claim that the population mean of such ratings is less than

8.008.00.

Assume that a simple random sample has been selected. Identify the null and alternative​ hypotheses, test​ statistic, P-value, and state the final conclusion that addresses the original claim.

1. Suppose that personal daily water usage in California is normally distributed with a mean of 17 gallons and a standard deviation of 6 gallons.

(a) What proportion of California’s population uses between 10 and 20 gallons daily?

(b) The governor of California wants to give a tax rebate to the 20% of the population that uses the least amount of water. What should the governor use as the maximum daily water usage for a person to qualify for the tax rebate?

(c) The governor randomly samples 100 people from the California population. What is the probability that the average usage among these 100 people is more than 18 gallons/day?

To study the effect of curing temperature on shear strength of a certain rubber compound, 80 specimens were cured at 150°C and 105 were cured at 130°C. The specimens cured at 150°C had an average shear strength of 620 psi, with a standard deviation of 20 psi. Those cured at 130°C had an average shear strength of 750 psi, with a standard deviation of 30 psi. Let μXμX represent the population mean strength for the specimens cured at 130°C and let μYμY represent the population mean strength for the specimens cured at 150°C. Find a 95% confidence interval for the difference μX−μYμX−μY . Round the answers to two decimal places.

2. A 95% confidence interval for ?? − ?? is (-4.5, -0.15). Based upon the data from which the confidence interval was constructed, someone wants to test H0: ?? = ?? versus HA: ?? ≠ ?? at the ? = 5% significance level.

(a) Based upon the confidence interval, what is your conclusion of the hypothesis test? Explain.

(b) Can we use the above confidence interval without any additional information to conduct the hypothesis test at the ? = 10% level? Why or why not?

A) Two arthroscopic surgeries were compared among patients suffering from osteoarthritis who had at least moderate knee pain. The lavage type has the joint flushed with fluid and no instrument is used to remove tissue; the debridement type has the joint flushed with fluid and an instrument is used to remove tissue. Knee pain scores, ranging from 0 to 100 with higher scores indicating severe pain, were obtained for patients randomly assigned to the two groups after the surgery and the results are given below:

------------Sameple Size--------Sample Mean-------Sample Standard Deviation

Lavage 11 59 24

Debridment 13 49 23

Determine a 95% confidence interval for the difference between the mean knee pain score for the lavage group and that for the debridement group

B) A test of abstract reasoning is given to a random sample of 10 students before and after completing a formal logic course. The results are shown below.

Before----------After

71 71

81 86

85 82

67 75

92 95

71 66

61 67

78 81

64 71

80 88

Determine a 95% confidence interval for the difference between the mean score after completing the course and the mean score before completing the course

C) The quality control officer collects a random sample of 100 yardsticks from the day's production run. The sample mean is 36 inches. The population standard deviation for that day’s production is σ =1 inches.

1)Find a 99% confidence interval for the mean length of all yardsticks made that day

2)The margin of error associated with the 99% confidence interval for the mean length of all yardsticks made that day is

3)You decide that margin of error in previous question is too large, and you want it to be at most 0.1 inches, what is the minimum sample size in order to obtain this margin of error with a confidence level of 99%?