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# Chi Square, confidence interval, regression, correlation

Question 1 Find the critical X ^2 corresponding to a sample size of 12 and a confidence level of 98 percent

a) 3.053

b) 24.725

c) 21.920

d) 3.816

Question 2 : Find confidence interval for population standard deviation, assuming population has a Normal distribution for the following: College student's annual earnings: 98% confidence, n = 9, Xbar ( sample average) = 3211, and s ( sample std. Dev.) = \$897

a) 566 < population standard deviation < 1978

b) 545< population standard deviation < 1755

c) 606 < population standard deviation < 1718

d) 706 < population standard deviation < 1170

Question 3: A study was conducted to compare the average time spent in the lab each week versus course grade for computer students. The results are recorded in the table below.
No of hours spent in the lab Grade ( percent )
10 96
11 51
16 62
9 58
7 89
15 81
16 46
10 51
Find the value of linear correlation coefficient r

a) -0.284

b) 0.017

c) 0.462

d) -0.335

Question 4: Use the given data to find the equation of the regression line. Round the final values to three significant digits, if necessary.
x y
1 143
3 116
5 100
7 98
9 90

a) y hat =140.4 - 6.2x

b) y hat = -140.4 + 6.2x

c) y hat =150.7 - 6.8x

d) y hat = - 150.7 + 6.8x

Question 5: Find the critical value that would be used in the test of correlation = 0 against H1: correlation not equal to zero, and determine if there is a significant linear correlation.
Significance Level is 0.05
test statistic r = 0.781
n =9

a) Critical value : r = ±0.666, no significant correlation
b) Critical value : r = ±0.666, significant correlation
c) Critical value : r = ±0.707, no significant correlation
d) Critical value : r = ±0.707, significant correlation

Please see the attached file for full problem description.

#### Solution Summary

Answers to Multiple Choice Questions on Chi Square, confidence interval for population standard deviation, linear correlation coefficient, equation of the regression line, significant linear correlation

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