Question

In? 1960, census results indicated that the age at which American men first married had a mean of 23.3 years. It is widely suspected that young people today are waiting longer to get married. We want to find out if the mean age of first marriage has increased since 1960. A random sample of??

4343

men who married for the first time last year was taken. The average age of the men in the sample was

2424

years with a standard deviation of

5.15.1

years.

a. Fill in the blanks. The? t-statistic for this problem is? ______ (round to 2 decimal places after the decimal? point) with? ______ degrees of freedom.

nothing

b. Use a calculator? (handheld or? online) to determine the? p-value. Which of the following is the correct range of the? p-value?

A.

0.005? < p-value? < 0.01

B.

p minus value less than 0.005p?value < 0.005

C.

0.01? < p-value? < 0.05

D.

0.05? < p-value? < 0.10

E.

p minus value greater than 0.10

Answer 1

a) The test statistic t = ()/(s/)

                                = (24 - 23.3)/(5.1/)

                               = 0.90

DF = 43 - 1 = 42

The t-test statistic for this problem is 0.90 with 42 degrees of freedom.

b) P-value = P(T > 0.90)

                = 1 - P(T < 0.90)

                = 1 - 0.8134

                = 0.1866

Option - E) P-value > 0.10