Using the data from 15 automobile accidents, the correlation coefficient between the combined speeds of the cars (x) in an accident and the amount of damage done (y) is 0.7831. The regression equation for the two variables is y = 801.518 + 162.845x.

a. Is this a significant correlation?

b. If the answer to last part is YES, then predict the amount of damage done in an accident in which the combined speeds of the car involved was 100 mph.

You wish to test the following claim (H1) at a significance level of α=0.01.

      Ho:μ=50.6
      H1:μ<50.6

You believe the population is normally distributed, but you do not know the standard deviation. You obtain the following sample of data:

What is the critical value for this test? (Report answer accurate to three decimal places.)
critical value =

What is the test statistic for this sample? (Report answer accurate to three decimal places.)
test statistic =

The test statistic is...

• in the critical region
• not in the critical region

This test statistic leads to a decision to...

• reject the null
• accept the null
• fail to reject the null

As such, the final conclusion is that...

• There is sufficient evidence to warrant rejection of the claim that the population mean is less than 50.6.
• There is not sufficient evidence to warrant rejection of the claim that the population mean is less than 50.6.
• The sample data support the claim that the population mean is less than 50.6.
• There is not sufficient sample evidence to support the claim that the population mean is less than 50.6.

Please explain how to do this problem on a TI-84 calculator. Thanks!!!

The National AIDS Behavioral Surveys interviewed a sample of adults in cities where AIDS is most common. This sample included 803 heterosexuals who reported having more than one sexual partner in the past year. We can consider this an SRS of size 803 from the population of all heterosexuals in high-risk cities who have multiple partners. These people risk infection with the AIDS virus. Yet 304 of the respondents said they never use condoms.

Find a 95% confidence interval for the population proportion that never use condoms?

2. A company recently opened two supermarkets in different areas. Management wanted to know if the average sales per day for the two supermarkets was different. A 35-day sample for Supermarket A produced an average daily sales of $ 53,700, with a standard deviation of $ 2,900. A 30-day sample for Supermarket B produced an average daily sales of $ 58,450, with a standard deviation of $ 3,100.

to. Build a 96% confidence interval to estimate the difference between the average daily sales for the two supermarkets.
b. Test at a 5% significance level if the average daily sales for the two supermarkets are different.
c. Interpret the conclusion obtained in part b.

Suppose that the sample unemployment rate for those aged 25–60 is 8% based on a survey of 150 people, while the unemployment rate for those aged 16–24 is 12% based on a survey of 100 people.

(a) Form a 90% confidence interval for the difference between the two population unemployment rates.

(b) Construct a test statistic to test the null hypothesis that the two population rates are the same against the alternative hypothesis that the rate is higher in for those aged 16–24, and report the associated P-value.

Efficiency experts study the processes used to manufacture items in order to make them as efficient as possible. One of the steps used to manufacture a metal clamp involves the drilling of three holes. In a sample of 70 clamps, the mean time to complete this step was

57.8 seconds. Assume that the population standard deviation is =σ  10

seconds. Round the critical value to no less than three decimal places

Construct a 90% confidence interval for the mean time needed to complete this step.

4.07. A taxi company manager is trying to decide whether the use of radial tires instead of regular belted tires improves fuel economy. Randomly selected 12 cars with radial tires yielded in a sample mean of 5.7 and sample standard deviation of 0.4, another randomly selected 15 cars with belted tires yielded a sample mean of 5.2 and a standard deviation of 0.8. Assume the populations to be approximately normal with equal variances.

State and conclude your hypothesis at the 0.05 level of significance based on manager’s claim?

Find P-Value.

Suppose that researchers study a sample of 50 people and find that 10 are left-handed.

(a) Find a 95% confidence interval for the population proportion that is left-handed.

(b) What would the confidence interval be if the researchers used the Wilson value ̃p instead?

(c) Suppose that an investigator tests the null hypothesis that the population proportion is 18% against the alternative that it is less than that. If α = 0.05 then find the critical value ˆpc. Using ˆp as the sample estimate, would the investigator reject the null? (d) Suppose that researchers are using this critical value but, unbeknownst to them, the true, population proportion is 0.16. Find the power of the test.

Describe a situation where you would use ANOVA by stating 1. the quantity of populations that are to be investigated, 2. a quantitative variable on these populations, 3. the sizes of samples from these populations, 4. your null hypothesis, 5. your alternative hypothesis, and 6. a significance level. Then find 7. The degrees of freedom of the numerator of your F-statistic, 8. the degrees of freedom of the denominator of your F-statistic, and state 9. what the P-value for your test statistic being less than your significance level would imply. Remember that you do not need to list the values of the variable for individuals in either the samples or the population, and that the values for 3 and 6 do not need to be calculated, only stated.

A study indicates that​ 18- to​ 24- year olds spend a mean of

140140

minutes watching video on their smartphones per month. Assume that the amount of time watching video on a smartphone per month is normally distributed and that the standard deviation is

1515

minutes. Complete parts​ (a) through​ (d) below.

a.

What is the probability that an​ 18- to​ 24-year-old spends less than

120120

minutes watching video on his or her smartphone per​ month?The probability that an​ 18- to​ 24-year-old spends less than

120120

minutes watching video on his or her smartphone per month is

nothing.

​(Round to four decimal places as​ needed.)

b.

What is the probability that an​ 18- to​ 24-year-old spends between

120120

and

170170

minutes watching video on his or her smartphone per​ month?The probability that an​ 18- to​ 24-year-old spends between

120120

and

170170

minutes watching video on his or her smartphone per month is

nothing.

​(Round to four decimal places as​ needed.)

c.

What is the probability that an​ 18- to​ 24-year-old spends more than

170170

minutes watching video on his or her smartphone per​ month?The probability that an​ 18- to​ 24-year-old spends more than

170170

minutes watching video on his or her smartphone per month is

nothing.

​(Round to four decimal places as​ needed.)

d.

OneOne

percent of all​ 18- to​ 24-year-olds will spend less than how many minutes watching video on his or her smartphone per​ month?

OneOne

percent of all​ 18- to​ 24-year-olds will spend less than

nothing

minutes watching video on his or her smartphone per month.

​(Round to two decimal places as​ needed.)

Here are summary statistics for randomly selected weights of newborn​ girls:

nequals=187187​,

x overbarxequals=32.132.1

​hg,

sequals=7.37.3

hg. Construct a confidence interval estimate of the mean. Use a

9090​%

confidence level. Are these results very different from the confidence interval

31.431.4

hgless than<muμless than<33.633.6

hg with only

2020

sample​ values,

x overbarxequals=32.532.5

​hg, and

sequals=2.82.8

​hg?

What is the confidence interval for the population mean

muμ​?

nothing

hgless than<muμless than<nothing

hg ​(Round to one decimal place as​ needed.)

Type the following table, which has historical world population data, into sheet 2 in rows 1 and 2.

Year 1000 1650 1800 1850 1900 1920 1930 World population, in millions 200 545 924 1171 1635 1834 2170 10.

Graph the above population data using the same steps as in Exercise 1. Add an exponential trendline, being sure to include the equation and R2 value in the chart. 11. In row 3 calculate the values for population predicted for each of the years by your exponential model (as you did in step 9 of exercise 1). You will need to use Excel’s “exp” function for the value of “e”, the base of your exponential model. The complete exponent must be included in parentheses as the input for the exp function. Note: Do not use “^” in the exp function. 12. In cell I1 enter the value 2008. 13. Drag your formula to cell I3. What does your model predict for the world population in 2008? 14. In a complete sentence, explain whether you believe this is realistic, and why. 15. Now let's use goal seek to calculate what year the population was 1 billion (1000 million). 16. Drag the formula from row 3 into cell J3. 17. Highlight cell J3 and click on tools then goal seek. 18. You want Excel to fill in the value in cell J1 so that the formula in J3 results in 1000. So in the pop-up box tell it to “set cell J3 to value 1000 by changing cell J1.” 19. According to your calculations, when was the world population 1 billion? 20. Looking at the actual population values in the table, how accurate do you think your calculation is?

A new program of imagery training is used to improve the performance of basketball players shooting free-throw shots. The first group did an hour imagery practice, and then shot 30 free throw basket shots with the number of shots made recorded. A second group received no special practice, and also shot 30 free throw basket shots. The data is below. Did the imagery training make a difference? Set alpha = .05.
Group 1: 15, 17, 20, 25 26, 27
Group 2: 5, 6, 10, 15, 18, 20

1. You must use all five steps in hypothesis testing:
A. Restate the question as a research hypothesis and a null hypothesis about the populations.
B. Determine the characteristics of the comparison distribution.
C. Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected.
D. Determine your sample’s score on the comparison distribution.
E. Decide whether to reject the null hypothesis.
2. Solve for and evaluate the effect size of this study using Cohen's D.
3. Create a 90% confidence interval for this problem.

Listed below are measured amounts of lead in the air. The EPA has established an air quality standard for lead of 1.5 μg/m³. The measurements shown below were recorded at Building 5 of the World Trade Center site on different days immediately following the attacks of Sep. 11. Use a 0.05 significance level to test the claim that the sample is from a population with a mean greater than the EPA standard. Is there anything about this data set suggesting the assumption of a normally distributed population might not be valid?

5.40     1.10     0.42     0.73     0.48     1.10

1.   Copy and paste the Minitab output for exercise into the document underneath the problem.   You are not also required to do these by hand, unless you want to.  

2. Write the rejection rule word for word as written here, "Reject Ho if the p-value is less than or equal to alpha."

3.   Write the actual p-value and alpha, then either "Reject Ho" or "Do not reject Ho." As an example: 0.0021 ≤ 0.05. True. Reject Ho.

4.    Write an English sentence stating the conclusion, claim, and significance level. As an example: If the claim is "Can we conclude that male business executives are taller, on the average, than the general male population at the  α  = 0.05 level?", and if we found our conclusion to be do not reject Ho, the sentence would be, "There is not enough evidence to conclude that  male business executives are taller, on the average, than the general male population at the  α  = 0.05 level."

During an angiogram, heart problems can be examined through a small tube threaded into the heart from a vein in the patient’s leg. It is important the tube is manufactured to have a diameter of 2.0mm. In a random sample of 12 tubes, the average was 2.025mm with a sample standard deviation of 0.021mm.

(a) Make a 99% confidence interval for the mean tube diameter. Conduct a Hypothesis test for mean tube diameter.

(b) What are the appropriate Null and Alternative Hypotheses

(c) Determine the appropriate reference distribution

(d) Calculate the test statistic

(e) Calculate the p-value

(f) What is your conclusion at the α = 0.01 significance level?

(g) What is your conclusion about the safety of the tubes being manufactured?

(h) Does the conclusion you reach from your hypothesis test agree with you answer in 3a? Explain