Statistical Methods for Psychology

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CHAPTER 7 Hypothesis Tests Applied to Means CHAPTER 7 Hypothesis Tests Applied to Means Objectives To introduce the t test as a ...

INCHAPTERS 5 AND6 we considered tests dealing with frequency (categorical) data. In those situations, the results of any experim ...

The rate at which the sampling distribution of the mean approaches normal as nin- creases is a function of the shape of the pare ...

see that just as the central limit theorem predicted, the distribution is approximately nor- mal, the mean is again at m550, and ...

7.2 Testing Hypotheses About Means—sKnown From the central limit theorem, we know all the important characteristics of the sampl ...

Because we know that the sampling distribution is normally distributed with a mean of 50 and a standard error of 2.58, we can fi ...

represent (1) a point on a distribution, minus (2) the mean of that distribution, all divided by (3) the standard deviation of t ...

and substitute sfor sto give Since we know that for any particular sample, is more likely than not to be smaller than the approp ...

in the sample. As. (The symbol is read “approaches.”) Since the skewness of the sampling distribution of disappears as the numbe ...

addition to being at risk for physical and developmental problems. The intervention program was designed to make mothers more aw ...

Section 7.3 Testing a Sample Mean When sIs Unknown—The One-Sample tTest 189 Table 7.1 Data and plots for LBW infants on Psychomo ...

This value will be a member of the t distribution on 56 2 15 55 dfif the null hypothesis is true—that is, if the data were sampl ...

For these data, n 5 10, 5 1.463, and s 5 0.341. A t test on is given by From Appendix t, with 10 2 15 9 dffor a two-tailed test ...

in this case the results also indicate that Kaufman and Rock’s experimental apparatus performed as it should.) For those who lik ...

Using the 1 0.244 and 2 0.244 separately to obtain the upper and lower limits for m, we have mupper5 10.244 1 1.463 5 1.707 mlow ...

percent of the time, a ring of specified width will encircle the parameter; 5% of the time, it will miss. A confidence statement ...

Section 7.4 Hypothesis Tests Applied to Means—Two Matched Samples 195 3.0 3.5 4.0 4.5 5.5 6.5 μ 5.0 6.0 7.0 Figure 7.6 Confidenc ...

samples, or dependent samples) and wish to perform a test on the difference between their two means. In this case we want what i ...

slope quite near 1.0. Such a slope suggests that how much the girl weighed at the begin- ning of therapy did not seriously influ ...