10) A credit score is used by credit agencies (such as mortgage companies and banks) to assess the creditworthiness of individuals. Values range from 300 to 850, with a credit score over 700 considered to be a quality credit risk. According to a survey, the mean credit score is

707.3.

A credit analyst wondered whether high-income individuals (incomes in excess of $100,000 per year) had higher credit scores. He obtained a random sample of

45

high-income individuals and found the sample mean credit score to be

720.9

with a standard deviation of

80.9.

Conduct the appropriate test to determine if high-income individuals have higher credit scores at the

=0.05

level of significance.

Question content area bottom

Part 1

State the null and alternative hypotheses.

H0:

greater than>

not equals

less than

equals=

enter your response here

H1:

equals=

less than

greater than>

not equals

enter your response here

(Type integers or decimals. Do not round.)

Part 2

Identify the t-statistic.

t0=enter your response here

(Round to two decimal places as needed.)

Part 3

Identify the P-value.

P-value=enter your response here

(Round to three decimal places as needed.)

Part 4

Make a conclusion regarding the hypothesis.

Fail to reject

Reject

the null hypothesis. There

is not

is

sufficient evidence to claim that the mean credit score of high-income individuals is

equal to

less than

greater than

enter your response here.

11)

The mean waiting time at the drive-through of a fast-food restaurant from the time an order is placed to the time the order is received is 86.6 seconds. A manager devises a new drive-through system that he believes will decrease wait time. As a test, he initiates the new system at his restaurant and measures the wait time for 10 randomly selected orders. The wait times are provided in the table to the right. Complete parts (a) and (b) below.	103.2	80.7
66.7	95.2
57.4	87.5
75.3	71.8
64.9	87.3

\fX Critical values Sample Size, n Critical Value Sample Size, n Critical Value 5 0.880 16 0.941 6 0.888 17 0.944 0.898 18 0.946 8 0.906 19 0.949 CO 0.912 20 0.951 10 0.918 21 0.952 11 0.923 22 0.954 12 0.928 23 0.956 13 0.932 24 0.957 14 0.935 25 0.959 15 0.939 30 0.960