The confidence interval for the population mean is

  a range of values which probably contains the population mean

  a range of values which contains the population mean

  the same from sample-to-sample

can only be determined for N less than 20

The df associated with evaluating the significance of robt are ____.

  N

  N  1

  N  2

  need more information

Exhibit 13-1 A researcher believes that women today weigh less than in previous years. To investigate this belief, he randomly samples 41 adult women and records their weights. The scores have a mean of 111 lbs. and a standard deviation of 12.4. A local census taken several years ago shows the mean weight of adult women was 115 lbs.

Refer to Exhibit 13-1. The obtained value of the appropriate statistic for testing H0 is ____.

  tobt = 2.07

  tobt = +3.07

tobt = 1.32

  tobt = +0.32

Refer to Exhibit 13-1. The df for determining tcrit = ____.

  41

  40

  39

  need more information

How many t distributions are there?

  1

  2

  30

  one for each value of df

If µ = 30,  = 5.2,  = 28.0, s = 6.1 and N = 13, the value of the most powerful statistic to test the significance of the sample mean is ____.

  1.18

  1.96

  2.18

  1.39

"Degrees of freedom" for any statistic is defined as ____.

  N

  N  1

 the number of scores that are free to vary in calculating the statistic

  N - 2