The table below shows a sample of waiting times​ (in days) for a heart transplant for two age groups. At α=​0.05, can you conclude that the variances of the waiting times differ between the two age​ groups?

A research study investigated the composition of wines from the Rhine and Moselle wine regionsof Germany. One component measured was the concentration of i-Butyl alcohol. The results ofthe study are listed in the following table:Region n i-Butyl alcohol (mg/100ml)Rhine 9 ̄x =5.32,s =2.24Moselle 14 ̄x =3.62,s =0.97(a) Assume that the underlying population variances from the two regions are identical. At the0.05 level of significance, test the null hypothesis that the mean concentration of i-Butylalcohol is the same for wines from the Rhine and Moselle regions.Construct a 95% confidence interval(b) Now assume that the underlying population variances from the two regions differ. At the 0.05level of significance, test the null hypothesis that the mean concentration of i-Butyl alcohol isthe same for wines from the Rhine and Moselle regions, construct a 95% confidence interval(c) If you were to provide a report to the investigators which of the above results would youinclude and why?

The average age of the library books is μ = 20 in California. This distribution is negatively skewed. But the librarian at the local elementary school claims that, on average, the books in the library are more than 20 years old. To test this claim, this librarian takes a sample of n = 16 books and records the publication date for each. The sample produces an average age of M = 23.8 years with a variance of s² = 67.5. Do the data from this sample provide evidence that the age of books in this local elementary school is older than the average age of population? Use α = .01

The Cadet is a popular model of sport utility vehicle, known for its relatively high resale value. The bivariate data given below were taken from a sample of Cadets, each bought new two years ago, and each sold used within the past month. For each Cadet in the sample, we have listed both the mileage  x (in thousands of miles) that the Cadet had on its odometer at the time it was sold used and the price y (in thousands of dollars) at which the Cadet was sold used. With the aim of predicting the used selling price from the number of miles driven, we might examine the least-squares regression line, =y−41.990.51x . This line is shown in the scatter plot below.   Based on the sample data and the regression line, complete the following.   (a)For these data, mileages that are less than the mean of the mileages tend to be paired with used selling prices that are ▼(Choose one) the mean of the used selling prices. (b)According to the regression equation, for an increase of…