Psyc 354: Hypothesis Testing
A researcher is interested in having as much ability as possible to identify a treatment effect if one really exists. Which of the following strategies should they employ?
change the sample size from n = 25 to n = 100
By selecting a smaller alpha level, it _____.
decreases the likelihood that H0 is rejected.
A two-tailed hypothesis test is being used to evaluate a treatment effect with α= .05. If the sample data produce a z-score of z = -2.24, which is the correct decision?
reject the null hypothesis and conclude that the treatment has an effect
A hypothesis test involves a comparison of which two elements?
research results from a sample and a hypothesis about a population
What is measured by the numerator of the z-score test statistic?
the distance between the sample mean and hypothesized population mean
Larry wants to do everything possible to be in a position to detect that a treatment he has designed is effective given that it is actually effective. Which of the following should he do?
use an alpha (α) of .05 instead of .01
An instructor is interested in whether frequent feedback in their course to a small sample of students influences student performance. The instructor knows that final class scores are normally distributed with µ = 85 and σ= 6. Which is the alternative hypothesis for this research study?
µfrequent feedback ≠ 85
Which statement below accurately describes the relationship between increasing the alpha level (for example, from a = .01 to a = .05), the size of the critical region, and the risk of a Type I error?
As the alpha level increases, the size of the critical region increases, and the risk of a Type I error increases.
If α = .05 for a two-tailed hypothesis test, how are the boundaries for the critical region determined?
Boundaries are drawn so there is 2.5% (.025) in each tail of the distribution.
A researcher administers a treatment to a sample from a population with a mean of µ = 60. If the treatment is expected to decrease scores, then the null hypothesis would state that µ ≥ 60.
F
It is possible for a very small treatment effect to be statistically significant.
T
The effect size is a measure of the magnitude of a treatment effect in standard error units.
T
A researcher selects a sample and administers a treatment for anxiety to the individuals in the sample. If the sample is used for a hypothesis test, what does the null hypothesis (H0) put forth about the treatment?
The treatment has no effect on anxiety.
The critical boundaries for a hypothesis test are z = +1.96 and z= -1.96. If the z-score for the sample data is z = -1.90, which is the correct statistical decision?
fail to reject H0
Which of the following is an accurate definition of a Type II error?
failing to reject a false null hypothesis