Compute the test statistic b. Compute the p-value.

Fran is training for her first marathon, and she wants to know if there is a significant difference between the mean number of miles run each week by group runners and individual runners who are training for marathons. She interviews 42 randomly selected people who train in groups and finds that they run a mean of 47.1 miles per week. Assume that the population standard deviation for group runners is known to be 4.4 miles per week. She also interviews a random sample of 47 people who train on their own and finds that they run a mean of 48.5 miles per week. Assume that the population standard deviation for people who run by themselves is 1.8 miles per week. Test the claim at the 0.01 level of significance. Let group runners training for marathons be Population 1 and let individual runners training for marathons be Population 2.   Step 2 of 3 :   Compute the value of the test statistic. Round your answer to two decimal places.

A marketing researcher wants to estimate the mean amount spent per year​ ($) on a web site by membership member shoppers. Suppose a random sample of 100 membership member shoppers who recently made a purchase on the web site yielded a mean amount spent of ​$58and a standard deviation of ​$55.Complete parts​ (a) and​ (b) below. a. Is there evidence that the population mean amount spent per year on the web site by membership member shoppers is different from ​$51​? ​(Use a 0.01 level of​ significance.)   State the null and alternative hypotheses.

Airline companies are interested in the consistency of the number of babies on each flight, so that they have adequate safety equipment. They are also interested in the variation of the number of Babies. Suppose that an airline executive believes the standard deviation in the number of babies is 6 at the most. The airline conducts a survey. The results of the 23 flights surveyed give a samle mean of 8 with a sample standard deviation of 9. Test the executive's belief to see if it is accurate, or if it is actually greater at the a = 0.05 level. Ho:o = H:o Select an answer df = P-value = The p-value is... greater than a less than (or equal to) a This test statistic leads to a decision to... reject the null fail to reject the null accept the alternative accept the null As such, the final conclusion is that there Select an answer v sufficient evidence to conclude the standard deviation of the number of babies on airplanes is Select an answer than (?

6.10 Males 20 to 29 years old have a mean height of 69.4 inches with a standard deviation of 3.5 inches. Females 20 to 29 years old have a mean height of 64.1 inches with a standard deviation of 3.1 inches. Find the standardized variable for the heights of males. Find the standardized variable for the heights of females. For a 68‐inch‐tall person, find the value of the standardized variable for males. For a 68‐inch‐tall person, find the value of the standardized variable for females. Compare your answer with part (c) and comment.

Suppose the mean number of candies in a standard vending machine bag is 47.6 with a standard deviation of 1.3 . assume that the number of candies is normally distributed what percentage of bags have less than 45 candies?

The president of a college wants to determine the mean number of units that college students take per semester. How large of a sample is required in order to be 99% sure that a sample mean will be off by no more than 1.25 units? An initial study suggested that the standard deviation is approximately 2.1 units.

Steve believes that his wife's cell phone battery does not last as long as his cell phone battery. On eight different occasions, he measured the length of time his cell phone battery lasted and calculated that the mean was 19.7 hours with a standard deviation of 9.4 hours. He measured the length of time his wife's cell phone battery lasted on twelve different occasions and calculated a mean of 18.9 hours with a standard deviation of 5.3 hours. Assume that the population variances are the same. Let Population 1 be the battery life of Steve's cell phone and Population 2 be the battery life of his wife's cell phone. Step 1 of 2: Construct a 90 % confidence interval for the true difference in mean battery life between Steve's cell phone and his wife's. Round the endpoints of the interval to one decimal place, if necessary.

According to the Bureau of Labor Statistics, the mean salary for registered nurses in Kentucky was $55,130. The distribution of salaries is assumed to be normally distributed with a standard deviation of $5,778. Someone would like to determine if registered nurses in Ohio have a greater average pay. To investigate this claim, a sample of 220 registered nurses is selected from the Ohio Board of Nursing, and each is asked their annual salary. The mean salary for this sample of 220 nurses is found to be $55,504.488.  Completely describe the sampling distribution of the sample mean salary when samples of size 220 are selected. mean:  μ x-bar = ____ standard deviation: σ x-bar  = ____ shape: the distribution of is ____________(not normally distributed/normally distributed) because ___________ (the sample size is large/the sample size is not large/the population of salaries is normally distributed/the population of salaries is not normally distributed)

In​ 2011, the mean property crime rate​ (per 100,000​ people) for 10 northeastern regions of a certain country was 2367. The standard deviation was 394. Assume the distribution of crime rates is unimodal and symmetric. What percentage of northeastern regions would you expect to have property crime rates between 1973 and 2761.