Location is known to affect the number, of a particular item, sold by Walmart. Two different locations, A and B, are selected on an experimental basis. Location A was observed for 9 days and location B was observed for 13 days. The number of the particular items sold per day was recorded for each location. On average, location A sold 39 of these items with a sample standard deviation of 9 and location B sold 51 of these items with a sample standard deviation of 6. Does the data provide sufficient evidence to conclude that the true mean number of sales at location A is fewer than the true mean number of sales at location B at the 0.05 level of significance? Select the [Alternative Hypothesis, Value of the Test Statistic]. a) [μ1 − μ2 ≠ 0, -0.3765] b) [μ1 − μ2 = 0, -3.765] c) [μ1 − μ2 < 0, t = −3.498] d) [μ1 − μ2 > 0, t = −3.498] e) [μ1 − μ2 ≠ 0, t = −3.498] f) None of the above

A researcher claims that the stomachs of blue crabs from Location A contain more fish than the stomachs of blue crabs from Location B. The stomach contents of a sample of 16 blue crabs from Location A contain a mean of 192 milligrams of fish and a standard deviation of 37 milligrams. The stomach contents of a sample of 11 blue crabs from Location B contain a mean of 189 milligrams of fish and a standard deviation of 45 milligrams. At α=0.01​, can you support the​ researcher's claim? Assume the population variances are equal. Complete parts​ (a) through​ (d) below.

Paint used to paint lines on roads must reflect enough light to be clearly visible at night. Researchers have 2 new types of paints they want to test – paint type A and paint type B. For each paint type, they tested if there was statistical evidence the average reflectometer reading is greater than 35. To test each type of paint, they used 15 paint samples. Further, suppose the standard deviation is the same for both types of paints. The sample mean for paint type A was 39 and the sample mean for paint type B was 41.5. For both statistical tests, the significance level is set to .05.Which of the following is true? If they fail to reject the null hypothesis for paint type A we can conclude there is statistical evidence the average reflectometer for type A paint is 35. The p-value for the type B paint test is smaller.     They rejected the null hypothesis for both paint types. Exactly two of the statements above are true. None are true.

Linda, a researcher in a technology company, obtained a sample of 270 smartphone owners from California. She wanted to investigate whether Californians were quicker or slower to buy the latest version of a smartphone than the people in the rest of the United States. Linda found the average number of days that Californians waited to buy the latest version of a popular smartphone to be 4. Smartphone owners in the rest of the country typically wait 6 days, with a standard deviation of 21.

It currently takes users a mean of 12 minutes to install the most popular computer program made by RodeTech, a software design company. After changes have been made to the program, the company executives want to know if the new mean is now different from 12 minutes so that they can change their advertising accordingly. A simple random sample of 91 new customers are asked to time how long it takes for them to install the software. The sample mean is 11.7 minutes with a standard deviation of 1.6 minutes. Perform a hypothesis test at the 0.05 level of significance to see if the mean installation time has changed.   Step 2 of 3 :   Compute the value of the test statistic. Round your answer to three decimal places.

A new drug is being tested to see if it reduces the frequency of migraines.  Study participants were divided into two groups.  49 participants in group 1 received the medication; 42 participants in group 2 received a placebo.  After a period of six months, group 1 had a mean of 4 migraines.  It is known that the population standard deviation for this group is 1.3 migraines.  Group 2 had a mean of 5.4 migraines.  The population standard deviation for this group is 1.7 migraines.  Can we conclude that the medication reduces the population mean number of migraines?  Use αα =0.01.  Note: If t-test, then unequal variances are assumed. Question a)Let:     μ1μ1 = the population mean number of migraines with the medication           μ2μ2 = the population mean number of migraines with the placebo (Step 1) State the null and alternative hypotheses by selecting the appropriate symbol, and identify which tailed test:     H0:H0: μ1μ1         μ2μ2     H1:H1: μ1μ1         μ2μ2     Which tailed test…

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.

Many people consider their smart phone to be essential! Communication, news, Internet, entertainment, photos, and just keeping current are all conveniently possible with a smart phone. However, the battery better be charged or the phone is useless. Battery life of course depends on the frequency, duration, and type of use. One study involving heavy use of the phones showed the mean of the battery life to be 11.25 hours with a standard deviation of 3.3 hours. Then the battery needs to be recharged. Assume the battery life between charges is normally distributed. (a) Find the probability that with heavy use, the battery life exceeds 12 hours. (Round your answer to four decimal places.)(b) You are planning your recharging schedule so that the probability your phone will die is no more than 5%. After how many hours should you plan to recharge your phone? (Round your answer to the nearest tenth of an hour.) hours

A researcher claims that the stomachs of blue crabs from Location A contain more fish than the stomachs of blue crabs from Location B. The stomach contents of a sample of 14 blue crabs from Location A contain a mean of 194 milligrams of fish and a standard deviation of 37 milligrams. The stomach contents of a sample of 8 blue crabs from Location B contain a mean of 184 milligrams of fish and a standard deviation of 44 milligrams. At a = 0.05, can you support the researcher's claim? Assume the population variances are equal. Complete parts (a) through (d) below. (a) Identify the null and alternative hypotheses. Choose the correct answer below. ОА. Но H1-H2 0 OD. Ho: H₁-12₂=0 Ha H1 H₂0 enough evidence at the 5% level of significance to support the researcher's claim.

A researcher claims that the stomachs of blue crabs from Location A contain more fish than the stomachs of blue crabs from Location B. The stomach contents of a sample of 13 blue crabs from Location A contain a mean of 191 milligrams of fish and a standard deviation of 37 milligrams. The stomach contents of a sample of 7 blue crabs from Location B contain a mean of 185 milligrams of fish and a standard deviation of 41 milligrams. At α=0.10​, can you support the​ researcher's claim? Assume the population variances are equal and that both samples are from normal populations. Complete parts​ (a) through​ (d) below.       ​(a) Identify the null and alternative hypotheses. Choose the correct answer below. A. H0​: μ1−μ2​=0 Ha​: μ1−μ2>0   B. H0​: μ1−μ2<0 Ha​: μ1−μ2=0   C. H0​: μ1−μ2=0 Ha​: μ1−μ2≠0   D. H0​: μ1−μ2​=0 Ha​: μ1−μ2<0   ​(b) Calculate the test statistic   t=? ​(Round to three decimal places as​ needed.)   ​(c) Calculate the​…