PY 211 Exam #2

Hypothesis testing is also called A) Type III error B) Random testing C) Effect size D) Significane testing

D) Significance testing

What do we typically accept as the probability of making a Type I error? A) 0.05 B) 1.96 C) 0.80 D) The power

D) The power

A measure of the size of an effect in a population is called A) Significance B) Probability C) Power D) Effect size

D) Effect size

The standard normal distribution is normally distributed with a mean of ____________. A) 0 B) 1 C) Any value D) Any positive value

A) 0

A researcher determines that students are active about 60 plus/minus 12 (M plus/minus SD) minutes per day. Assuming these data are normally distributed, what is the z-score for students being active 48 minutes per day? A) 1.0 B) -1.0 C) 0 D) There is not enough information to answer this question

B) -1.0

A counselor records the number of disagreements (per session) among couples during group counseling sessions. If the number of disagreements is distributed normally as M = 4.4 (SD = 0.4) disagreements, then what proportion of couples disagree X = 4 or fewer times during each counseling session? A) 0.3413 B) 0.1587 C) 0.8413 D) The probability is not listed in the unit normal table

B) 0.1587

A professor gives an exam in which the mean score is 78 points. She gives another exam to test whether or not scores change. In this example, the null hypothesis is A) μ (not)= 78 B) M (not)= 78 C) μ = 78 D) M = 78

C) μ = 78

The unit of measurement distributed along the x-axis of a standard normal distribution is referred to as a A) Standard score b) X-score c) Normalized deviation D) Z-score

D) Z-score

A researcher determines that students study an average of 80 plus/minus 20 (M plus/minus SD) minutes per week. Assuming these data are normally distributed, what is the z-score for students studying 100 minutes per week? A) 1.0 B) -1.0 C) 0.3413 D) 0.1587

A) 1.0

The probability of committing a Type II error is stated by _____________. A) Beta B) Alpha C) A p value D) The power

A) Beta

Scores close to the mean are located in the _____________ of a normal distribution. A) Body B) Tails C) Most sensitive areas D) Most uncertain areas

A) Body

The following distribution most closely approximates a A) Normal distribution B) Positively skewed distribution C) Negatively skewed distribution D) Mutimodal distribution

A) Normal distribution

A researcher directly controls for the probability of a __________, but does not directly control for the probability of a _______________. A) Type I error; alpha level B) Type II error; beta level C) Type I error; Type II error D) Type II error; Type I error

A) Type I error; alpha level

The standard normal distribution is normally distributed with a standard deviation of _______________. A) 0 B) 1 C) Any value D) Any positive value

B) 1

A researcher selects a sample of 64 participants from a population with a mean of 10 and a variance of 16. What is the standard error of the mean? A) 10 B) 2.0 C) 0.5 D) There is not enough information to answer this question

B) 2.0

A distribution of all sample means that could be obtained in samples of a given size from the same population is called A) A conditional procedure B) A sampling distribution C) Sampling without replacement D) Random sampling

B) A sampling distribution

Regardless of the distribution of the population, the sampling distribution of sample means will be approximately normally distributed. What characteristic of the mean explains this? A) Unbiased estimator B) Central limit theorem C) Minimal variance D) None of the above

B) Central limit theorem

What is the central limit theorem? A) It explains the sample means will vary minimally from the population mean B) It explains that a sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution in the population C) It explains that if we select a sample at random, then on average we can expect the sample mean to equal the population mean D) All of the above

B) It explains that a sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution in the population

Based on the effect size conventions, d = 0.60 is a A) Small effect size B) Medium effect size C) Large effect size

B) Medium effect size

Most behavior is believed to ___________ a normal distribution. A) Be exactly equal to B) Not resemble at all C) approximate

C) Approximate

Which of the following is required to locate proportions of area under the normal curve? A) Compute a z-transformation B) Find the probability of a z-score in the unit normal table C) Both A and B D) None of the above

C) Both A and B

A researcher finds that the average preschool-aged child drinks M = 2 cups of milk per day. Assuming these data are normally distributed, the z-score for the average cups per day (X = 2) in this example is A) Less than 0 B) Greater than 0 C) Exactly equal to 0 D) There is not enough information to answer this question

C) Exactly equal to 0

A method for testing a claim or hypothesis about a parameter in a population, using data measured in a sample, is called A) Random sampling B) Level of significance C) Hypothesis testing D) Guessing

C) Hypothesis testing

What does it mean to say that the sample mean is an unbiased estimator of the population mean? A) The sample means will vary maximally from the population mean B) The sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution is the population C) If we select a sample at random, then on average we can expect the sample mean to equal the population mean D) All of the above

C) If we select a sample at random, then on average we can expect the sample mean to equal the population mean

A researcher reports that the size of an effect in some population is d = 0.88. Which of the following is an appropriate interpretation for d? A) The effect observed in the population was significant B) Mean scores were significant by 0.88 points in the sample C) Mean scores were significant by 0.88 points in the population D) Mean scores shifted 0.88 standard deviations in the population

C) Mean score were significant by 0.88 points in the population

The ____________ converts any normal distribution with any mean and any variance to a standard normal distribution. A) Normal distribution B) Standard normal distribution C) Standard normal transformation D) Unit normal table

C) Standard normal transformation

Scores for from the mean are located in the _______________ of a normal distribution. A) Body B) Tails C) Most sensitive areas D) Most uncertain areas

B) Tails

Experimental research is typically conducted using a sampling strategy in which A) The order of selecting participants matters B) The same participant can never be selected twice in the same sample C) Participants are replaced after being sampled D) All of the above

B) The same participant can never be selected twice in the same sample

A researcher obtains z = 1.45 for a one-independent sample z-test. What is the decision for this test at a 0.05 level of significance, two-tailed? A) To reject the null hypothesis B) To retain the null hypothesis C) It depends on whether the test is one-tailed or two-tailed D) There is not enough information to make a decision

B) To retain the null hypothesis

The probability of committing a Type 1 error is stated by_______________. A) Beta B) Alpha C) A p value D) The power

B) alpha