A teacher wants to know whether the children in her class are performing significantly better on a standardized math test compared to the national average. The national mean score is μ = 85, the national standard deviation is σ = 25, and the mean score in her class (n = 25) is M = 92.5. Use α = .05. What is the z-score for this sample mean?

When is there a risk of a Type II error?

Which of the following is an accurate definition for the power of a statistical test?

Students in Dr. Gallimore’s class took an exam: the mean was an 85 with a standard deviation of 2. What was the proportion of students who received an exam score between 88 and 92?

For a normal population with µ = 40 and σ = 10 which of the following samples has the highest probability of being obtained?

Imagine that you conducted a hypothesis test examining how automobile ownership (i.e., someone owns an automobile or does not own an automobile) affects happiness (measured by a survey). You found that people who do not own automobiles tend to be significantly happier than those that do own an automobile. You then computed the effect size, d = 0.75. a) Why is it important to compute an effect size? b) Please interpret the Cohen’s d value (d = 0.75) by explaining what it means in terms of automobile ownership and happiness.

What is the consequence of a Type I error?

What proportion of a normal distribution is located between the mean and z = 1.40?

For a normal population with a mean of 80 and a standard deviation of 10, what is the probability of obtaining a sample mean greater than M = 75 for a sample of n = 25 scores?

Which of the following accurately describes the effect of increasing the sample size?