Sampling & Probability
Ch. 5.4
A Type II error occurs whenever a(n): _________ null hypothesis is not rejected.
Incorrect
Ch. 6.2
In a normal distribution, _____% of the scores fall below the mean.
50%
Ch. 6.2
The process of converting individual raw scores in a normal distribution to a set of scores for which the percentiles are already known is called:
Standardization
Ch. 5.1
The two types of errors possible in hypothesis testing are:
Type I and Type II
Ch. 5.1
The use of random assignment indicates that the researcher is conducting which type of study?
an experiment
Ch. 6.1
What will happen to a distribution of scores in a sample if the number of scores increases?
The distribution of scores in a sample will approach normality (become more normal)
Ch. 6.2
To what percentile does a z score that falls between 0 and −1.0 roughly correspond?
34th percentile
Ch. 6.3
The standard deviation for the distribution of means is also called:
standard error
Ch. 5.2
When a person pays attention to evidence that confirms what they already believe and ignores evidence that would disconfirm their beliefs, they are demonstrating _____ bias.
Confirmation
Ch. 6.1
The normal curve has three defining characteristics. These are:
1. Unimodal
2. Symmetric
3. Defined Mathematically
Ch. 6.2
A z-score of -2.0 would indicate scores that were at or below the ______________ percentile.
2nd percentile / ~2.86%
Ch. 5.2
In the absence of many trials, one cannot determine true probabilities of events. However, over the long run, and numerous trials, the expected relative-frequency probability of events is very clear and predictable. This is known as the:
law of large numbers.
Ch. 5.3
In a study designed to investigate the link between sugar and hyperactivity, a researcher assigns one group of children to eat a high-sugar snack and another group of children to eat a snack with no sugar. The control group in this experiment was the:
group of children assigned to eat a no sugar snack.
Ch. 6.1
When a normal distribution has exactly 50% of scores that fall below the mean and 50% that fall above the mean, it is considered (or described as) ________.
Symmetrical
Ch. 6.2
It is known that the mean weight of the population of newborn infants is 7.5 pounds, with a standard deviation of 1.1 pounds. What is the weight (in pounds) of a newborn infant with a z score of +0.5?
8.05 pounds
Ch. 6.3 (will need calculator)
The population of all standardized exam scores has a mean of 500 and a standard deviation of 100. Twenty-five students in a professor's class take the exam, and their average score (mean) is 525.
What is the z score that is associated with the class's average (mean)?
+1.25
Ch. 5.4
A counselor tests a new therapy with their clients. At the end of six months, they find that the therapy significantly lowered anxiety symptoms. In other words, they rejected the null hypothesis. If the null hypothesis is actually true, the counselor has made what error?
Type I error
Ch. 6.2 (need calculator)
The mean SAT score for seniors who took the test in 2022 was 1050. If the standard deviation for this same year was 209, what is the raw score for a person with a z score of +1.50?
1363.5
Ch. 6.3
What is the standard error for a distribution of sample means with a population standard deviation of 15 and a sample size of 36?
2.50
Ch. 6.3
If σ = 50 and N = 100, then σM =
5