4. According to the credit rating agency Equifax, credit limits on newly issued credit cards increased between January 2011 and May 2011. Suppose that random samples of 400 new credit cards issued in January 2011 and 500 new credit cards issued in May 2011 had average credit limits of $2635 and $2887, respectively. Suppose that the sample standard deviation for these two samples were $365 and $412 respectively. Assume that the population standard deviations for the two populations are unknown and unequal. a) Let μ₁ and ₂ be the average credit limits on all credit cards issued in January 2011 and in May 2011, respectively. Construct a 98% confidence interval for H₁ - H₂. b) At a 1% significance level, can you conclude that the average credit limit for all new credit cards issued in January 2011 was lower than the corresponding average for all credit cards issued in May 2011? Use the Critical Value Approach to make this test.
4. According to the credit rating agency Equifax, credit limits on newly issued credit cards increased between January 2011 and May 2011. Suppose that random samples of 400 new credit cards issued in January 2011 and 500 new credit cards issued in May 2011 had average credit limits of $2635 and $2887, respectively. Suppose that the sample standard deviation for these two samples were $365 and $412 respectively. Assume that the population standard deviations for the two populations are unknown and unequal. a) Let μ₁ and ₂ be the average credit limits on all credit cards issued in January 2011 and in May 2011, respectively. Construct a 98% confidence interval for H₁ - H₂. b) At a 1% significance level, can you conclude that the average credit limit for all new credit cards issued in January 2011 was lower than the corresponding average for all credit cards issued in May 2011? Use the Critical Value Approach to make this test.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question
![4. According to the credit rating agency Equifax, credit limits on newly issued
credit cards increased between January 2011 and May 2011. Suppose that
random samples of 400 new credit cards issued in January 2011 and 500 new
credit cards issued in May 2011 had average credit limits of $2635 and $2887,
respectively. Suppose that the sample standard deviation for these two samples
were $365 and $412 respectively. Assume that the population standard
deviations for the two populations are unknown and unequal.
a) Let μ₁ and μ₂ be the average credit limits on all credit cards issued in
January 2011 and in May 2011, respectively. Construct a 98% confidence interval
for
М1 - М2.
b) At a 1% significance level, can you conclude that the average credit limit for
all new credit cards issued in January 2011 was lower than the corresponding
average for all credit cards issued in May 2011? Use the Critical Value Approach
to make this test.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F66301e59-a86d-47c0-9dd8-21e24614422a%2F36734ca1-5ebf-40e5-937b-d3a9a52948e4%2F14o6wol_processed.png&w=3840&q=75)
Transcribed Image Text:4. According to the credit rating agency Equifax, credit limits on newly issued
credit cards increased between January 2011 and May 2011. Suppose that
random samples of 400 new credit cards issued in January 2011 and 500 new
credit cards issued in May 2011 had average credit limits of $2635 and $2887,
respectively. Suppose that the sample standard deviation for these two samples
were $365 and $412 respectively. Assume that the population standard
deviations for the two populations are unknown and unequal.
a) Let μ₁ and μ₂ be the average credit limits on all credit cards issued in
January 2011 and in May 2011, respectively. Construct a 98% confidence interval
for
М1 - М2.
b) At a 1% significance level, can you conclude that the average credit limit for
all new credit cards issued in January 2011 was lower than the corresponding
average for all credit cards issued in May 2011? Use the Critical Value Approach
to make this test.
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