A recent study focused on the number of times men and women send a Twitter message in a day. The information is summarized here:    Sample Size Sample Mean Population Standard Deviation Men 31 29 5 Women 36 34 10 At the 0.01 significance level, we ask if there is a difference in the mean number of times men and women send a Twitter message in a day. Assume that women are Population 1 and men are Population 2. What is the value of the test statistic for this hypothesis test?   a. 2.907   b. 2.641   c. 2.815   d. 2.911

Question: In a survey of buying habits, 400 women shoppers are chosen at random in super market 'A' located in a certain section of the city. Their average weekly food expenditure is dollar 250 with a standard deviation of Dollar 40. For 400 women shoppers chosen at random in super market 'B' in another section of the city, the average weekly food expenditure is Dollar 220 with a standard deviation of Dollar 55. Test at 1% level of significance whether the average weekly food expenditure of the two populations of shoppers are equal.

Pop. Mean Stand. Dev. Sample size 1 73.00 10.00 6.00 14 2 62.50 8 1.Independent random samples are selected from two populations. Below are selected summary statistics. (a) Construct the 95% confidence interval for μx-µY. (b) Obtain the P-value for the alternative µx =µY.

An insurance agent claims that the average age of Age last Number of policy-holders who insure through him is less than the average age for all birthday (yrs) the agents, which is 30-5 years. A random sample of 100 policy-holders who had insured through him gave the adjoining age distribution. Calculate the mean and standard deviation of the sample and use it to test the claim that the average is less than the figure for all the agents at 5% level of significance persons 16-20 12 21-25 22 26 30 20 31-35 30 36-40 16

Fewer young people are driving. In 1995, 63.9% of people under 20 years old who were eligible had a driver's license. Bloomberg reported that percentage had dropped to 41.7% in 2016. Suppose these results are based on a random sample of 1,200 people under 20 years old who were eligible to have a driver's license in 1995 and again in 2016. a. At 95% confidence, what is the margin of error and the interval estimate of the number of eligible people under 20 years old who had a driver's license in 1995? Margin of error (to four decimal places) Interval estimate to (to four decimal places) b. At 95% confidence, what is the margin of error and the interval estimate of the number of eligible people under 20 years old who had a driver's license in 2016? Margin of error = (to four decimal places) Interval estimate = to (to four decimal places) c. Is the margin of error the same in parts (a) and (b)? - Select your answer v Why, or why not?

Question 2 In 2015, the average duration of long-distance telephone calls from a certain town was 3.9 minutes. A telephone company wants to perform a test to determine whether this average duration of long- distance calls has changed. Fifty calls, originating from the town, was randomly selected and the following summary minutes. Σx= 205 E(x - x)? = 56.43 a) Calculate the sample mean, &. b) Calculate the sample standard deviation c) Using the p value approach at the 1% level of significance, test whether the mean duration of long-distance calls from the town had increased. d) Construct the 99% confidence interval for the population mean duration of the long-distance calls from the town.

Is it true or false that the least absolute deviations (LAD) estimator minimizes the sum of the absolute value of the population errors.

15 To perform a test of hypothesis that the population slope parameter is zero, the test statistic t is ______. a 14.487                 b 16.097                 c 17.885                 d 19.873

Exhibit 10-1 Salary information regarding two independent random samples of male and female employees of a large company is shown below. Sample size Sampe mean salary (in $1000s) Population variance Male 64 44 128 Female 36 41 72 Refer to Exhibit 10-1. At 95% confidence, we have enough evidence to conclude that the O a. average salary of males is significantly lower than females O b. salaries of males and females are equal O c. average salary of males is significantly greater than females O d. null hypothesis fails to be rejected

Question: Godrej soap manufacturing company was distributing a particular brand of soap through a large number of retail shops. Before a heavy advertisement campaign, the mean sales per week per shop was 140 dozens. After the campaign, a sample of 26 shops was taken and the mean sales was found to be 147 dozens with standard deviation 16. Can you consider the advertisement effective?