代做Set #8、代写CS/Python, C/C++程序语言、代做fixed-rate loans

日期：2018-11-09 10:13

Problem Set #8:

Hypothesis Testing Using the χ

2 Distribution

Problem 1. Home mortgage interest rates for 30-year fixed-rate loans vary throughout the

country. During the summer of 2000, data available from various parts of the country suggested

that the standard deviation of the interest rates was .096. The corresponding variance

in interest rates would be (.096)2 = .009216. Consider a follow-up study in the summer of

2001, The interest rates for 30-year fixed rate loans at a sample of 20 lending institutions had

a sample standard deviation of .114. Conduct a hypothesis test of H0 : σ

2 = .009216 using

α = .05 to see whether the sample data indicate that the variability in interest rates changed.

Problem 2. On the syndicated Siskel and Ebert television show, the hosts often created the

impression that they strongly disagreed about which movies were best. An article in Chance

reported the results of ratings of 160 movies by Siskel and Ebert. Each review is categorized

as Pro (“thumbs up”), Con (“thumbs down”), or Mixed.

Ebert Rating

Con Mixed Pro

Con 24 8 13

Siskel Rating Mixed 8 13 11

Pro 10 9 64

Test whether Siskel’s and Ebert’s ratings are independent using a .01 level of significance.

Problem 3. The Wall Street Journal’s Shareholder Scoreboard tracks the performance of 1000

major U.S. companies. The performance of each company is rated based on the annual total

return, including stock price changes and the reinvestment of dividends. Ratings are assigned

by dividing all 1000 companies into five groups from A (top 20%), B (next 20%), to E (bottom

20%). Shown here are the one-year ratings for a sample of 60 of the largest companies. Do the

largest companies differ in performance from the performance of the 1000 companies in the

Shareholder Scoreboards? Use α = .05.

A B C D E

5 8 15 20 12

1

Problem 4. The number of incoming phone calls at a company switchboard during 1-minute

intervals is believed to have a Poisson distribution. Use α = .01 and the following data to test

the assumption that the incoming phone calls follow a Poisson distribution.

Number of Calls Observed Frequency

0 150

1 310

2 200

3 150

4 130

5 40

6 20

Problem 5. Use α = .01 and conduct a goodness of fit test to see whether the following sample

appears to have been selected from a normal distribution: {55, 86, 94, 58, 55, 95, 55, 52, 69,

95, 90, 65, 87, 50, 56, 55, 57, 98, 58, 79, 92, 62, 59, 88, 65}. Construct a histogram of the data and

discuss whether the histogram supports the conclusion reached with the goodness of fit test.