A college professor claims that the entering class this year appears to be smarter than entering classes from previous years. He tests a random sample of
10
of this year's entering students and finds that their mean IQ score is
121
, with standard deviation of
14
. The college records indicate that the mean IQ score for entering students from previous years is
111
. If we assume that the IQ scores of this year's entering class are normally distributed, is there enough evidence to conclude, at the
0.1
level of significance, that the mean IQ score,
μ
, of this year's class is greater than that of previous years?
Perform a onetailed test. Then fill in the table below.
Carry your intermediate computations to at least three decimal
places and round your answers as specified in the table. (If
necessary, consult a list of formulas.)

This is the right tailed test .
The null and alternative hypothesis is
H_{0} : = 111
H_{a} : > 111
Test statistic = t
= (  ) / s / n
= (121  111) / 14 / 10
= 2.259
Test statistic = 2.259
degrees of freedom = 9
= 0.1
Critical value = 1.383
Reject the null hypothesis .
Yes
Get Answers For Free
Most questions answered within 1 hours.