A researcher in the field of biostatistics is interested in the long term effects of COVID-19 on lung function. She obtains a random sample of 1000 adults and performs a spirometry test to measure the amount of air the lungs can hold. It is known that adults have an average spirometer score of 70. The adults in this study score an average of 67 with a sample standard deviation of 6.   Which type of statistical test should the researcher do?  a. one sample t-test b. one sample z-test c. two sample t-test d. not enough information to determine

Answer part a and b

At a local store, 65 female employees were randomly selected and it was found that their mean monthly income was $625 with a standard deviation of $121.50. Seventy-five male employees were also randomly selected and their mean monthly income was found to be $667 with a standard deviation of $168.70. Test the hypothesis that male employees have a higher monthly income than female employees. Use α = 0.01.

A random sample of 81 tourists in Chattanooga showed that they spent an average of $2000(in a week) with a standard deviation of $100 and a sample of 64 tourists in Ontario showed that they spent an average of $2500(in a week) with a standard deviation of $144. We are interested in determining if there is any significant difference between the average expenditures of those who visited the two cities? Test the hypothesis at alpha=0.05 and write all the steps.

The Road Department is trying to see whether they should buy road treatments ( in tons) for storms based on the number of inches of snow for each recorded. Use  Pearson r at alpha- 0.05 to test the hypothesis.   ILLUSTRATE THE NORMAL CURVE inches in snow  1.5 1.7 3.7 2.8 4.6 2.4 3.1 2.9 3.6 4.2 3.1 number of tons  805 905 1235 1000 1302 998 1102 1305 1456 1600 1005

. Differences of electric potential occur naturally from point to point on a body’s skin. Researchers used newts to determine if changing the electric field reduces the mean healing rate for all newts. The researchers found in a sample of 14 newts the following data results: ?̅= −5.714 with sd = 10.564. Conduct a paired t-test at α = .01 to determine if there is sufficient evidence to conclude that changing the electric field reduces the mean healing rate for all newts.

Patients with rheumatoid arthritis are at a greater risk of developing osteoporosis. The reasons are not well understood due to the difficulty in qualitatively assessing bone metabolism and mineral content. A researcher measures human calcitonin (HCT) levels in men with rheumatoidarthritis. The researcher randomly selects 43 men with rheumatoid arthritis and measured the  mean HCT level of 33.8 pg/mL. Assume that HCT for individuals with rheumatoid arthritis follows a normal distribution with standard deviation σ = 23.6 pg/mL. 3. Create a 95% confidence interval for the population mean HCT.

A one-sample test of H0: μ = 125 against Ha: μ > 125 is carried out based on sample data from a Normal population with standard deviation 15. The SRS of size 15 produced a mean 132.8 and standard deviation 12.6.   What is the P-value of the test in this situation?

A simple regression analysis is performed to relate maintenance expense (Y, dollars per month) to usage (X, hours per week). A random sample of 82 observations showed an F-statistic of 10 in the ANOVA table, and the scatter plot suggested that maitenance expense increases as usage increases. The sample variance of Y is 100. Question 17. The sample correlation coefficient between X and Y is closest to O 1/4 O 1/9 O 1/5 O 1/2 O 1/3 o ooo o

Consider the following questions about CIs. A researcher tests emotional intelligence (EI) for a random sample of children selected from a population of all students who are enrolled in a school for gifted children. The researcher wants to estimate the mean EI for the entire school. The population standard deviation, mean, for EI is not known. Let’s suppose that a researcher wants to set up a 95% CI for IQ scores using the following information: The sample mean M= 130 The sample standard deviation s = 15. The sample size N = 120.  The df = N – 1 = 119 What are the upper and lower limits of the CI and the width of the 95% CI if all the other values remain the same (M = 130, s =15) but you change the value of N to 16?       For N = 16, lower limit = 122.41 and upper limit=137.58 width (upper limit-lower limit = 15,17 What are the upper and lowers of CI and the width of 95% CI if all the other values remain the same but you change the value of N to 25? . For N = 25, lower limit =…