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
of this year's entering students and finds that their mean IQ score is
, with standard deviation of
. The college records indicate that the mean IQ score for entering students from previous years is
. If we assume that the IQ scores of this year's entering class are normally distributed, is there enough evidence to conclude, at the
level of significance, that the mean IQ score,
, of this year's class is greater than that of previous years?
Perform a one-tailed 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
H0 : = 111
Ha : > 111
Test statistic = t
= ( - ) / s / n
= (121 - 111) / 14 / 10
Test statistic = 2.259
degrees of freedom = 9
Critical value = 1.383
Reject the null hypothesis .
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