Statistics Questions & Answers

(Multiple Choice) A \( 95 \% \) confidence interval for the mean price of textbooks at UCLA in the spring quarter of 2010 , based on a random sample taken by statistician David Diez, was ( \( \$ 58.30 \), \( \$ 86.14 \) ). To obtain this interval, he multiplied the standard error by 2.04 , which was the value of \( t^{*} \). What would have been the effect if he had multiplied the standard error by 1.70 instead? Choose the best answer. (a) The confidence interval would have been wider. (b) The confidence interval would have been narrower. (c) The confidence level would have been higher. (d) The confidence level would have been lower. (e) Answers a and c are both correct. (f) Answers b and d are both correct.

03. (Multiple Choice) A \( 95 \% \) confidence interval for the mean price of textbooks at UCLA in the spring quarter of 2010 , based on a random sample taken by statistician David Diez, was ( \( \$ 58.30 \), \( \$ 86.14 \) ). Assuming that nothing else changed, what would have been the effect of on the confidence interval if the sample size had been smaller? Assume that the necessary conditions for finding the confidence interval hold. Choose the best answer. (a) The confidence interval would have been wider. (b) The confidence interval would have been narrower. (c) The confidence level would have been higher. (d) The confidence level would have been lower. (e) Answers a and c are both correct. (f) Answers b and d are both correct.

02. A study of the longleaf pine trees in Wade Tract in Thomas County, Georgia measures the diameter at breast height (DBH) for each tree. This is the diameter of the tree at 4.5 feet and the units are in centimeters \( (\mathrm{cm}) \). Only trees with DBH greater than 1.5 cm were sampled. A random sample of 40 trees had mean DBH 27.9 cm and standard deviation 17.7 cm . We are interested in whether the mean DBH of the longleaf pine tree is greater than 25 cm . (a) State the hypotheses for this problem. (b) Calculate the value of the test statistic. (c) Calculate and interpret the p-value. (d) State your conclusion in terms of the problem.

1. A consumer advocate wants to find out whether the soft drinks sold at a fast-food restaurant contains less than the advertised 16 ounces. A random sample of 10 independently chosen drinks produced a mean of 16.5 ounces and standard deviation of 0.4 ounces. Assume that the distri- bution of serving sizes in the population is Normally distributed. (a) State the null hypothesis in both words and symbols, using \( \mu \) as the population mean weight of all the drinks labeled 16 ounces at this fast-food restaurant. (b) State the alternative hypothesis in both words and symbols. (c) Carry out the appropriate test. Explain what conclusion the consumer advocate should reach. (d) Explain why no calculations are needed to show that the population mean is not significantly less than 16 ounces.

(a) A yoga instructor collected student data. She found that students who had less sleep did no motion during class. What can she conclude? There is no correlation between amount of sleep and range of motion. There is a correlation between amount of sleep and range of motion. There may or may not be cau done to determine this. There is a correlation between amount of sleep and range of motion. There is probably also causat increase in the range of motion with an increase in the amount of sleep.

Jim is assessing the popularity of his high school football team's website for the first 5 weeks after the season ends. The average number of visits on the website for 5 weeks is given in the table below.The initial number of visits to the website was _. The percent decrease from 4th week to 5th week was __%. The minimum number of visits on the website in the first 5 weeks since Jim began his assessment was _.

Activity 206 At the same Spaza shop where you bought the chips, they also sell toffees in 4 flavours: \( \checkmark \) Chocolate, Caramel, Mint and Vanilla \( \checkmark T=[ \) chocolate, caramel, mint, vanilla \( ] \) If you may only buy a maximum of 1 per flavour, make use of a binary table to determine the possible selections (number of subsets in set \( T) \).

Find the mean (average) of the following set of numbers. 7, 5, 2, 5, 2, 9.

Galculater Q Question 65 Hint? Find the mean (average) of the following set of numbers. \( 7,5,2,5,2 \)

Data set X: 5, 9, 9, 13Data set Y: 5, 9, 9, 13, 27The lists give the values in data sets X and Y. Which statement correctly compares the mean of data set X and the mean of data set Y?A) The mean of data set X is greater than the mean of data set Y.B) The mean of data set X is less than the mean of data set Y.C) The means of data set X and data set Y are equal.D) There is not enough information to compare the means.