In a study of How Undergraduate Students Use Credit Cards, it was reported in 20
ID: 3156833 • Letter: I
Question
In a study of How Undergraduate Students Use Credit Cards, it was reported in 2009 that undergraduate students have a mean credit card balance of $3173. This figure was an all-time high and had increased 44% over the previous five years. Assume that a current study is being conducted to determine if it can be concluded that the mean credit card balance for undergraduate students has continued to increase compared to the April 2009 report. Based on previous studies, use a population standard deviation of = $1000.
Choose a sample of 180 undergraduates with a sample mean credit card balance of $3325. State the null and alternative hypotheses for this problem. You will use the Critical Value approach to hypothesis testing. At the 0.01 level of significance, what is your critical value(s)?
Explanation / Answer
a. State the null and alternative hypotheses
H0: u<=3173
Ha: u>3173
Z=(3325-3173)/1000/sqrt(180) = 2.04
P=1-z(2.04)= 0.0207
Reject H0 since p value is <=.05. credit card balance has increased.