As sample size increases, the:
standard error decreases
If an effect is significant but the effect size for the difference between the two means is small (according to Cohen's conventions), about how much overlap will there be between the two distributions?
85 percent
According to Cohen's convention, a value of _____ is a large effect size.
0.8
It becomes progressively easier to declare statistical significance as the _____ increases.
Sample Size
What falls within a 90 percent confidence interval?
all the means we would expect to obtain 90 percent of the time when repeatedly sampling from a population
A confidence interval is a(n) _____ that includes the population mean after repeatedly sampling.
-point estimate
-interval estimate
-probability
-hypothesis
Interval Estimate
Mehl (2007) published a study in the journal Science reporting the results of an extensive study of 396 men and women comparing the number of words uttered per day by each sex. He found that on average women uttered 16,215 words a day and men uttered 15,6
Means of men & women are not even one-tenth of 1 standard deviation apart
The sample mean is _____ the confidence interval.
-at the beginning of
-at the end of
-in the center of
-excluded from
in the center of
Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49. According to Cohen's c
NOT SMALL
According to Cohen's convention, a value of _____ is a small effect size.
0.2
0.5
0.8
340
0.2
Why are effect sizes rather than test statistics used when comparing study results?
-Effect sizes, unlike test statistics, are not affected by sample size and thus ensure a fair comparison.
-It is easier to average effect size than it is to average test s
Effect sizes, unlike test statistics, are not affected by sample size and thus ensure a fair comparison.
As sample size increases, the test statistic increases because the:
-difference between the means increases.
-overlap between distributions increases.
-distance between distributions decreases.
-standard error decreases.
NOT DIFFERENCE BETWEEN THE MEANS INCREASES
When alpha increases, both _____ and _____ increase.
-standard error; power
-power; probability of a Type I error
-power; probability of a Type II error
-probability of a Type I error;
-probability of a Type II error
power; probability of a Type I error
If a researcher performs a meta-analysis and finds that the mean d = 0.11, and that the 95 percent confidence interval around this mean is (-0.04, 0.26), what could the researcher conclude?
-All future studies of this effect will find effect sizes somewhe
NOT D
Measures of effect size:
NOT 'INCREASE AS SAMPLE SIZE INCREASES
It is known that the population mean for the verbal section of the SAT is 500 with a standard deviation of 100. In 2006, a sample of 400 students whose family income was between $70,000 and $80,000 had an average verbal SAT score of 511. The point estimat
511; [501.2, 520.8]
Before hypothesis testing and at the beginning of a study, a researcher is advised to conduct _____ because it _____.
-a power analysis; tells the researcher the number of participants needed for trustworthy results
-an effect size estimate; tells the res
a power analysis; tells the researcher the number of participants needed for trustworthy results
When Cohen's d is large (based on Cohen's conventions), the amount of overlap between the two distributions being compared is _____ percent.
-75
-53
-15
-0
53
Before conducting a power analysis, a researcher should know the desired:
-alpha level
-gender distribution
-standard error.
-variance.
alpha level
If an effect is significant but the effect size for the difference between the two means is small (according to Cohen's conventions), about how much overlap will there be between the two distributions?
-99 percent
-85 percent
-50 percent
-15 percent
85 percent
A researcher interested in the effects of humor on memory randomly assigns 16 participants to either the humor group or the no-humor group. The humor group reads humorous sentences and the no-humor group reads non-humorous sentences. On a later memory tes
Because the effect looks as though it is barely missing significance, and her sample size is fairly small, she can increase her sample size to increase her statistical power to detect the effect.
If the sample mean is 56.2, with an upper limit to the confidence interval of 59.94, what is the lower limit?
-58.07
-54.33
-52.46
-50.89
52.46
Confidence in a point estimate _____, whereas confidence in an interval estimate _____.
-is very high; is very low
-is based on the alpha level used; is based on the margin of error calculated
-cannot be articulated; is directly related to the size of the
cannot be articulated; is directly related to the size of the interval constructed
What falls within a 90 percent confidence interval?
-all the means we would expect to obtain 10 percent of the time when repeatedly sampling from a population
-all the means we would expect to obtain 90 percent of the time when repeatedly sampling from a
all the means we would expect to obtain 90 percent of the time when repeatedly sampling from a population
Imagine that a study of memory and aging finds that younger participants correctly recall 55 percent of studied words, older participants correctly recall 42 percent of studied words, and the size of this effect is Cohen's d = 0.49. This effect size indic
older participants is approximately half a standard deviation below that of younger participants.