Chapter Six Stats

A therapist goes through her records and finds that 200 of her 400 patients showed significant improvement in mental health over the past year. Hence, the probability of her patients showing significant improvement in mental health is .05 .50 200 400

0.50

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? unbiased estimator central limit theorem minimal variance none of the above

central limit theorem

what is sem

standard error of measurement

Experimental research is typically conducted using a sampling strategy in which the order of selecting participants matters the same participant can never be selected twice in the same sample participants are replaced after being sampled all of the above

the same participant can never be selected twice in the same sample

State whether the first area is bigger, the second area is bigger, or the two areas are equal: the area to the right of the mean, or the area between z = ±1.00. The first area is bigger. The second area is bigger. The two areas are the same. The second area is bigger.

the second area is bigger

The normal distribution has all of the following characteristics, except that it is symmetrical its distribution is theoretical the total area under the curve is greater than 1.0 the mean, median, and mode are equal

the total area under the curve is greater than 1.0

The mean can take on any value and the standard deviation can take on any positive value. Therefore, scores above the mean are distributed the same as scores below the mean extreme scores are possible in a normal distribution there are an infinite number of possible normal distributions this characteristic has no practical implication

there are an infinite number of possible normal distributions

A news poll showed that voters had no preference for either of three candidates. In this example, the probability of a vote for, say, Candidate A equals 1/2 1/3 2/3 1.00

1/3

What does it mean to say that the sample mean is an unbiased estimator of the population mean? The sample means will vary minimally from the population mean. The sampling distribution of possible sample means is approximately normally distributed, regardless of the shape of the distribution in the population. If we select a sample at random, then on average we can expect the sample mean to equal the population mean. all of the above

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

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

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

A parent decides to reward her child if he eats an average of at least five bites of his vegetables at dinner during the first week. She finds that her child ate 4 + 0.8 (M + SD) bites per meal for the first week. Assuming these data are normally distributed, should this parent reward her child? Yes, because the z score for 5 bites is greater than 0. Yes, because the z score for 5 bites is less than 0. No, because the z score for 5 bites is greater than 0. No, because the z score for 5 bites is less than 0.

No, because the z score for 5 bites is greater than 0.

A researcher randomly selects a sample of athletes and reports that their average score on a health and fitness scale is 23. Based on the characteristics of the sample mean, what does this say about the mean in the population? Nothing; it was just a sample. There is no way to know without knowing the size of the sample. We expect that the population mean is equal to 23 because the sample mean is an unbiased estimator of the population mean.

We expect that the population mean is equal to 23 because the sample mean is an unbiased estimator of the population mean.

A sampling distribution of the sample mean or variance is a distribution of all measures that could be obtained in a given sample of a given size a distribution of all scores that could be obtained in samples of a given size from one or more populations a distribution of all scores that could be obtained in a population a distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population

a distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population

A distribution of all sample means or sample variances that could be obtained in samples of a given size from the same population is called ' a conditional procedure a sampling distribution sampling without replacement random sampling

a sampling distribution

A researcher increases the sample size, which will: Increase the value of standard error decrease the value of standard error reduce variability in the population increase variability in the population

decrease the value of standard error

The mean of the sampling distribution of sample means is equal to the population mean equal to the population variance both A and B none of the above

equal to the population mean

A researcher finds that the average preschool-aged child drinks two cups of milk per day. Assuming these data are normally distributed, the z score for the average cups per day in this example is less than 0 greater than 0 exactly equal to 0 There is not enough information to answer this question.

exactly equal to 0

Which type of sampling is most often applied by researchers in the behavioral sciences? theoretical sampling normal sampling experimental sampling standard normal sampling

experimental sampling

Suppose you select a sample of three people from a population of four (A, B, C, D). Which of the following samples is possible using the experimental sampling strategy? persons A, C, and A persons A, D, and D persons B, C, and D persons B, A, and B

persons B, C, and D