2. Suppose a random sample of 52 National Football League players from Greensboro had an average weight of 252.5 pounds with a standard deviation of all players in the league being 31.1 pounds. Determine the 80% and 89% confidence intervals for this sample. 3. Assume a student from North Carolina A&T claims that the average time some horticultural products from North Carolina A&T State University Farm takes before they expire is reported to be 11 hours and that the standard deviation for one of the products is 30 minutes. A random sample of 50 of the same product had an average fresh life of 10.7 hours. Use the 90% confidence interval to test the student's claim.

In a sample of 80 business trips taken by employees in the HR department, a company finds that the average amount spent for the trips was $1580 with a standard deviation of $350. In a sample of 80 trips taken by the employees in the sales department is $1750 with a standard deviation of $550. When testing the hypothesis that the averageamount spent on trips taken by the salesepartment are higher than those taken by the HR department, if the test statistic is 2.33 and the critical value is 1.96 then what is your conclusion concerning the null hypothesis?     Reject the null hypothesis     Fail to reject the null hypothesis

A study is conducted to compare the performance of students with more than one personal electronic gadget and those with only one. A number of them were taken as subjects for the study. The mean grades of these students and the standard deviations are shown below:  For one gadget:  The mean is 83, standard deviation is 12, and sample size is 7.  For more than one gadget: The mean is 79, standard deviation is 13, and sample size is 5.  Is it possible to conclude that there is no significant difference in the mean grades of the two types of students at a 95% confidence interval? Note: This is a two-tailed test. Also take note that this is finding the difference between two population means.

A manufacturer advertises that the average life of batteries produced by his firm is at least 12 months. The consumer board disagrees, and claims that the average life of the batteries is less than 12 months. The consumer board test a random sample of 9 batteries and find that the mean life is 10.6 months with a standard deviation of 2. The consumer board's alternative hypothesis is:   A. The average life of the population of batteries is 12 months. B. The average life of the population of batteries is less than 12 months. C. The average life of the population of batteries is more than 12 months. D. The average life of the population of batteries is at least 12 monthsThe manufacturer of 'Road King' tyres claim that their tyres last an average of 70,000km or more. The Consumer Board suspects that this claim may be false (they have received some complaints) and decide to test the manufacturer's claim. The Consumer Board took a sample of size 500 from the population. They ran the…

. Each member of a large genetics class grows 12 pea plants from an independent pea family. Each family is expected to have 3/4 plants with smooth peas and 1/4 plants with wrinkled peas. a. On average, how many wrinkled pea plants will a student see in her 12 plants? b. What is the standard deviation of the proportion of wrinkled pea plants per student? c. What is the variance of the proportion of wrinkled pea plants per student? d. Predict what proportion of the students saw exactly two wrinkled pea plants in their sample.

Suppose population 1 is all blue cars sold at used car auctions, and the mean sale price of all such blue cars is $24,579 with a standard deviation of $3,691. Additionally suppose population 2 is all red cars sold at used car auctions, and the mean sale price of all such red cars is $21,948 with a standard deviation of $4,028. If a simple random sample of 47 blue cars sold at used car auctions is selected and the mean sale price of the 47 blue cars in the sample is determined, and if an independent simple random sample of 59 red cars sold at used car auctions is selected and the mean sale price of the 59 red cars in the sample is determined, if appropriate describe completely the sampling distribution of X1 - X2? 8. What is the shape of the sampling distribution? Skewed Left Skewed Right Bimodal Normal   9. Are there any unusual features in this sampling distribution? Yes No

Consider the following service system. The average inter-arrival time is 10 minutes, and the standard deviation of the inter-arrival time is 10 minutes. The average processing time is 5 minutes with the standard deviation of the processing time being 6 minutes. What is the value of Iq? What is the value of I?

In one city, the average amount of time that tenth-graders spend watching television each week is 23 hours. The principal of Birchwood High School believes it is less for the 10th grade students that at his school.  For a sample of 95 tenth-graders from the school, the mean amount of time spent watching television per week was 21.9 hours.  Assuming a population standard deviation of 3.1 hours, does the data provide sufficient evidence to conclude that for all tenth-graders at Birchwood High school, the mean amount of time spent watching television per week is less than the city average of 23 hours?  Perform the appropriate hypothesis test using a significance level of 0.005.  What are the hypotheses?         What is the test statistic? Is it a z or a t?         Find the P-value for this test statistic. How does it compare to the significance level?  On the normal curve, indicate the location of the test statistic  and  the p-value. (label them on the graph)                 Write…

A researcher is conducting a study to determine the mean trough dosage of medication for a population. Assume a previous study was conducted for the same medication and the mean trough dose was found to be 490 mg with a standard deviation of 30 mg. If the researcher wants to be 95% confident the true mean trough dosage of the medication is within 10 mg of the true mean trough dosage, what sample size is needed if the study is predicted to have an 76% retention rate? n = 50 n = 71 n = 47 n = 104