Need help with these MC questions :)

QUESTION 'I To determine the difference in fuel consumption between the Mazda 2 and the Mazda 3, ten cars of each model were selected, and driven around a race course by one of 20 different drivers. The distance travelled per litre of fuel was recorded for each run. How should this data be analyzed? 0 a. Paired sample t-test. O b. Two sample test of proportion. O c. One sample ttest. 0 d. Two independent sample ttest QUESTION 2 A researcher is investigating a new financial awareness program, designed to reduce the amount of money people spend on credit cards. She randomly selects 20 people with credit cards to put through the program. She obtains the records of money spent in the year before the program, as well as the amount of money spent in the year after the program, and conducts the appropriate 2-sample t-test. What is the correct number of degrees of freedom forthis test? 0 a. 20 O b.38 O c. 19 O d.40 QUESTION 3 A shopper was interested in comparing prices between Woolworths and Coles. He found the cost of the same 12 items at 7 randomly selected Woolworths stores and 9 randomly selected Coles stores. Let W; be the price at the i-th Woolworths store and C; be the price at the i-th Coles store. The following data was obtained: W = $72.34 IS Sw = $5.86 C = $68.26 Sc = $4.92 What is the pooled estimate of the standard deviation? O a. $5.34 O b. $5.41 O c. $5.32 O d. $5.39