(This calculation can be done on the TI-83/84 as follows: let L1 = observed values; let L2 = expected
values; let L3 = (L2-L1 ) 2 /L2 ; Then χ 2 = LIST MATH sum(L3) =3.33. )
In a chi-square goodness-of-fit test, the number of degrees of freedom equals one less than the number
of possible outcomes. In this case, df = n –1 = 4 – 1 = 3.
From Chapter 6
The correct answer is (e). There are 101 terms, so the median is located at the 51st position in an
ordered list of terms. From the counts given, the median must be in the interval whose midpoint is 8.
Because the intervals are each of width 2, the class interval for the interval whose midpoint is 8 must
be (7, 9).
- From Chapter 13
The correct answer is (c). df = 13 – 2 = 11 t = 3.106 (from Table B; if you have a TI-84 with the
invT function, t = in v T(0.995,11 )). Thus, a 99% confidence interval for the slope is:
0.0365 ± 3.106(0.0015) = (0.032, 0.041).
We are 99% confident that the true slope of the regression line is between 0.032 units and 0.041
units. - From Chapter 10
The correct answer is (c). - From Chapter 8
The correct answer is (b). In an experiment, the researcher imposes some sort of treatment on the
subjects of the study. Both experiments and observational studies can be conducted on human and
nonhuman units; there should be randomization to groups in both to the extent possible; they can both
be double blind. - From Chapter 7
The correct answer is (c). III is basically what is meant when we say R-sq = 98.1%. However, R-sq
is the square of the correlation coefficient.
could be either positive or negative, but not both. We can’t tell direction from
R 2 . - From Chapter 11
The correct answer is (e). The power of a test is the probability of correctly rejecting H 0 when H (^) A
is true. You can either fail to reject H 0 when it is false (Type II), or reject it when it is false (Power).
Thus, Power = 1 – P (Type II) = 1 – 0.26 = 0.74.
From Chapter 14
The correct answer is (d). There are 81 observations total, 27 observations in the second column, 26
observations in the first row. The expected number in the first row and second column equals