BESC Exam 2 (No formula's)

When choosing a level of alpha for a hypothesis test, unless you have a compelling reason to do otherwise, you should use... .01 .10 .05 .50

.05

What is the point estimate for the population mean if the sample mean is 55, the population standard deviation is 15, and the sample size is 25? 10-20 55 3 Cannot be calculated without additional information

55

Which is more accurate: a point estimate or a confidence interval? They are equally accurate A point estimate A confidence interval Cannot be determined without additional information

A confidence interval

Which is more precise: a point estimate or a confidence interval? A point estimate Cannot be determined without additional information They are equally precise A confidence interval

A point estimate

What is one important difference between a point estimate and a confidence interval? The point estimate cannot be used for inferring population values A point estimate gives a single value but a confidence interval gives a range of values The confidence interval can be used only for unbiased statistics but a point estimate can be used for any kind of statistics The point estimate is based on sample data instead of population data

A point estimate gives a single value but a confidence interval gives a range of values

For which measures is it possible to compute a confidence interval? Any population parameter Only unbiased measures Only the population mean Only measures with normally distributed scores

Any population parameter

What is meant by a "manipulation" in the context of experimental research? The creation of emotions against the participant's will An unethical practice The physical control of a respondent's body Any variable that is controlled by the researcher

Any variable that is controlled by the researcher

A bar chart would work best for which of the following measurement scales? Categorical levels Quantitative levels Ordinal or ratio Nominal or interval

Categorical levels

Assuming that the null hypothesis is actually false, then what is the easiest way to make sure that it will be rejected? Decrease n Increase the critical value Increase n Decrease the effect size

Increase n

What is the lowest level of measurement needed to calculate the mean? Interval Ordinal Ratio Any level but the distribution must be symmetrical

Interval

When n increases, what happens to a confidence interval? It is unchanged It becomes less biased It becomes wider It becomes narrower

It becomes narrower

In a positively skewed distribution, which measure will generally have the highest value? Mode All are the same Median Mean

Mean

Which measure of central tendency works best of negatively skewed distributions? Median Mean No measure is appropriate Mode

Median

In a negatively skewed distribution, which measure will generally have the highest value? Median All are the same Mode Mean

Mode

What is the lowest level of measurement needed to calculate the mode? Any level but the distribution must be symmetrical Interval Any level that doesn't have outliers Nominal

Nominal

If a researcher conducts a z-test and does not reject the null hypothesis, then... None of the other choices is correct the researcher has proven that the null hypothesis is true. it is not appropriate to calculate an effect size. the researcher must gather new data

None of the other choices is correct

Imagine two samples that are drawn from the same population and measure the same variables in the same way. Sample A has a narrower confidence interval than Sample B does. Which sample likely has the larger n? They are the same Sample B Sample A Cannot be determine without additional information

Sample A

Imagine two studies that are identical in every respect except the size of their samples. Sample A has an effect size of d = .50 and a p-value of .07. Sample B has an effect size of d = .50 and a p-value of .04. Which sample likely had the smaller sample size? Cannot be determined without additional information Sample B They are the same Sample A

Sample A

Imagine two studies that are identical in every respect except their p-values and effect sizes. Sample A has a sample size of n = 60 and a p-value of .02. Sample B has a sample size of n = 60 and a p-value of .08. Which sample likely had the larger effect size? They are the same Sample B Cannot be determined without additional information Sample A

Sample A

Imagine that two samples - Sample A with n = 10 and Sample B with n = 50 - are drawn from the same population and confidence intervals are computed for the same variables, which sample will have the narrower confidence interval? Sample A Sample B Cannot answer without additional information They will be the same

Sample B

Which measure requires a degrees of freedom calculation? Population range Population variance Sample mean Sample standard deviation

Sample standard deviation

What does it mean when the result of a z-test is called "statistically significant"? The null hypothesis has been proven false The results can be generalized to other populations The alternate hypothesis has been proven true The alpha value was greater than the p-value

The alpha value was greater than the p-value

If you conduct a one-sample z-test, you would test... the hypothesis that the experimental group has a lower average score than the population. The null hypothesis of no difference between the group's mean and the population mean. whether the sample was representative. the hypothesis that the experimental group has a higher average score than the population.

The null hypothesis of no difference between the group's mean and the population mean.

When a sample comes randomly from the general population but that sample's mean is nonetheless significantly different from the population's, then... a sampling error has been made. a Type II error has occurred. a Type I error has occurred. the researcher should gather new data.

a Type I error has occurred.

A sampling distribution can be calculated for... sample means only. population means only. any unbiased statistic. any sample statistic.

any sample statistic.

If a distribution of raw scores is completely uniform, then, given a sufficiently large n, the sampling distribution of means for that distribution will... be normal. be uniform. have a slight positive skew. have a slight negative skew.

be normal.

When the range of confidence for a confidence interval becomes lower - from 95% to 90%, for example - then the confidence interval will... be more skewed. be less accurate. become wider. become narrower.

become narrower.

When the standard deviation increases, the confidence interval will... become narrower. become more normal. become wider. stay the same.

become wider.

Imagine that a researcher is interested in whether students who receive an experimental teaching method have higher standard test scores than the national average. What would be an appropriate alternate hypothesis for a one-tailed or directional z-test for this test? experimental students' average = national average None of these choices are appropriate experimental students' average < national average experimental students' average > national average

experimental students' average > national average

In statistics, "estimation" refers to using sample data to... calculate the sample variance. determine the effects of missing data in the sample. infer a population parameter. calculate the degrees of freedom.

infer a population parameter.

A histogram is appropriate when the data are... nominal or ordinal. ordinal. interval or ratio. nominal, interval, or ratio.

interval or ratio.

In a one-tailed or directional test for a one-sample z-test, if the observed value of z is greater than the critical value of z, then the null hypothesis... is not rejected (i.e., retained). must be replaced with a two-tailed or nondirectional hypothesis. is rejected. is proven false.

is rejected.

Data is generally gathered from samples instead of populations because... it is easier to calculate statistics for samples. samples have greater value of kurtosis than populations do. it may be impossible to gather data from populations. population are more biased than samples.

it may be impossible to gather data from populations.

A confidence interval specifies a range of values for a parameter estimate, whereas a point estimate specifies... the probability that the estimate is accurate. the degree of bias in the estimate. the degree of precision of the estimate. just a single value for that parameter.

just a single value for that parameter.

If you want to use a one-sample z-test, you must first... know the population standard deviation. choose measures that yield ratio level data. delete any outliers from the sample data. recruit a diverse sample of participants.

know the population standard deviation.

A bell curve (i.e., a normal distribution) is... uniform. platykurtic. leptokurtic. mesokurtic.

mesokurtic.

If a person's employment is coded as Unemployed = 0 or Employed = 1, then that variable is at the ______ level of measurement. ordinal interval nominal ratio

nominal

The lowest level of measurement (i.e., the one that contains the least information) is the ______ level of measurement. ratio interval ordinal nominal

nominal

The Central Limit Theorem states that as the number of sample means in the distribution increases, the shape of a sampling distribution becomes closer to a... bimodal distribution. normal distribution. uniform distribution. skewed distribution.

normal distribution.

As the size of samples (n) in a sampling distribution increases, the shape of that distribution becomes more... normal. uniform. similar to the original population distribution. variable.

normal.

According to the central limit theorem, when all possible samples of a sufficient size are taken from a bimodal population and their means are charted, that distribution of means will be... normally distributed. skewed towards the greater of the two modes. uniform. bimodally distributed.

normally distributed.

As n increases, the point estimate for the mean will... not change. become more precise. become higher. become less biased.

not change.

If you can use only one number to estimate a population parameter, then the best value is a... point estimate. null hypothesis. confidence interval. probability value.

point estimate.

The number of small businesses opened in a county each year is an example of which level of measurement? ratio nominal interval ordinal

ratio

If a researcher is using an critical value of ±1.96 for a z-test and gets an observed (or test) z of -2.73, then the researcher should... use a one-tailed test instead. retain (i.e., fail to reject) the null hypothesis. reject the null hypothesis. change the critical value to a smaller value.

reject the null hypothesis.

If a researcher is using an alpha of .05 for a z-test and gets an observed (or test) p-value of .06, then the researcher should... reject the null hypothesis. change the alpha to a larger value. use a one-tailed test instead. retain (i.e., fail to reject) the null hypothesis.

retain (i.e., fail to reject) the null hypothesis.

As the mean for a sample becomes greater, the width of the corresponding confidence interval will... increase. change depending on the level of kurtosis. stay the same. decrease.

stay the same.

According to the Central Limit Theorem, the mean of the sampling distribution of means -μX¯¯¯¯¯μX¯- will equal... the mean of the original population divided by n-1. Cannot be predicted without additional information. the mean of the original population. the mean of the original population divided the square root of n.

the mean of the original population.

If you draw a picture of the null distribution with the critical values and regions of rejection marked, then the alpha level is represented by... the proportion of the distribution between the critical values. the location of the observed sample values. the proportion of the distribution in the regions of rejection. the height of the distribution at the critical values.

the proportion of the distribution in the regions of rejection.

If a researcher is using alpha = .05 and gets a p-value for the z-test of p = .02, then... the results are unlikely to occur by chance if the null hypothesis is true. this proves that the null hypothesis is false. Cohen's d = alpha/p = .05/.02 = 2.5 the results are likely to occur by chance if the null hypothesis is true.

the results are unlikely to occur by chance if the null hypothesis is true.

A Type I error occurs when... the sample data deviate substantially from normality. the sample is too small for hypothesis testing. the sample data lead a researcher to retain (i.e., fail to reject) a null hypothesis that is, in fact, false. the sample data lead a researcher to reject a null hypothesis that is, in fact, true.

the sample data lead a researcher to reject a null hypothesis that is, in fact, true.

A Type II error occurs when... the sample data deviate substantially from normality. the sample data lead a researcher to reject a null hypothesis that is, in fact, true. the sample data lead a researcher to retain (i.e., fail to reject) a null hypothesis that is, in fact, false. the sample is too small for hypothesis testing.

the sample data lead a researcher to retain (i.e., fail to reject) a null hypothesis that is, in fact, false.

If a researcher is comparing a sample mean to a population mean and gets Cohen's d = 0, this means that... the sample mean is the same as the population mean. a mistake was made because Cohen's d cannot be zero. the sample distribution has no variability. the effect is statistically significant.

the sample mean is the same as the population mean.

A point estimate for the population mean is based on... the sample size. the sample mean. leptokurtic data only. the sampling distribution of means.

the sample mean.

When calculating an effect size for the z-test... you must know the Type I and Type II error rates. the sample size is irrelevant. the data must be normally distributed. you must use the standard error.

the sample size is irrelevant.

The distribution of all possible sample means (of a given size) is called... the population of raw scores. the sampling distribution of means. the distribution of samples. the distribution of means.

the sampling distribution of means.

When the distribution of all possible samples of a given size are taken from a population and their means are charted, that distribution is known as... the potential mean distribution. the sampling distribution of means. a standard mean distribution. the sample distribution.

the sampling distribution of means.

If a person were to create a sampling distribution for sample standard deviations, then the mean of that distribution would be equal to... the mean of the original distribution. the standard deviation of the original distribution. Cannot be calculated without additional information. the square root of the standard deviation of the original distribution.

the standard deviation of the original distribution.

The standard error is... the standard deviation of the sampling distribution. equal to the population mean divided by n-1. a measure of how much calculations will vary if mistakes are made. the measure of sample bias.

the standard deviation of the sampling distribution.

In order to calculate a one-sample z-test you need... to know the population mean and variance/standard deviation. to have data that consists of nominal variables. to estimate the population variance/standard deviation. to have uniformly distributed data.

to know the population mean and variance/standard deviation.

If the formula for the population standard deviation were used with sample data, then result would be... identical. impossible to calculate. too small. too big.

too small.

If scores in a data set are very different from each other, then, compared to when they are more similar to each other, the standard deviation... will be biased for the sample. will be low. will be high. cannot be calculated.

will be high.

What is the symbol for the standard error? σx¯¯¯σx¯ σμσμ σn√σn μσ

σx¯¯¯σx¯

The equation for the standard error of a sampling distribution is... σσ/n−−√n σσ/(n - 1) μμ/σσ μμ/n−1−−−−−√

σσ/n−−√n