BESC 3010 Final
What are the values of skewness and Kurtosis for a normal distribution?
skewness=0 Kurtosis=0
What is the symbol for standard error
sigma X bar
Imagine a sample with n=16, mean of 52 that comes from a population. SD of 12 95% CL
(46.12, 57.88)
If a test has a population mean of 140 and a standard deviation of 12 then what is the z-score for the sample of n=9 scores with a mean of 136
-1 (z-score for a sample)
What is the sample standard deviation for the following data? 2, 2, 3, 4, 4
0.80 (standard deviation for a sample formula)
If a positively skewed distribution of 132 scores with a mean of 49 and a standard deviation of 14 is standardized then the new distributions mean will be...?
1
If a distribution has a mean of 200 and a standard deviation of 40 then what is the standard error for a sample of 400 scores?
2
If a distribution has a mean of 70 and a standard deviation of 4, then what is the z-score for a sample of 64 scores with a mean of 71?
2
If a population has a mean of 40 and a standard deviation of 9, what would the z-score be for a sample of 9 people with a mean of 46?
2
If a population has a mean of 60 and a standard deviation of a, what is the z-score for a sample of 144 people with an average of 62?
3
If the population mean for a distribution is 150 and the standard deviation is 10, then what is the z-score for a sample of 100 people with an average score of 153
3
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?
55
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?
Sample A
When a sample comes randomly from the general population but that sample's mean is nonetheless significantly different from the populations then...
a Type I error has occurred
When a distribution of raw scores is converted to z-scores, the shape of the distributions...
approaches a normal distribution
In a positively skewed distribution the extreme scores are_______
at the high end
When the range of confidence for a confidence interval becomes lower- from 95% to 90%, for example- then the confidence interval will...
become narrower
What is the range for this data set? 5, 3, 7+, 1, 4
cannot be calculated
Imagine that a researcher is interested in whether students who receive an experimental teaching method have 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
Assuming that the null hypothesis is actually false, then what is the easiest way to make sure that it will be rejected?
increase n
What is the minimum level of measurement needed to calculate the mean?
interval
A histogram is appropriate when the data is...
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 rejected
Which of the following is a defining characteristic of experiments?
manipulation
In a positively skewed distribution, which measure will generally have the highest value?
mean
Which measure of central tendency is MOST influenced by outliers?
mean
Which measure of central tendency works best of negatively skewed distributions?
median
A bell curve (i.e., a normal distribution) is...
mesokurtic
In a negatively skewed distribution which measure will generally have the highest value?
mode
If a person's employment is coded as Unemployed=0 or Employed=1, then that variable is at the _______ level of measurement
nominal
If a person's sex is recorded as "Male" or "Female," then that variable is at the _____ level of measurement.
nominal
What is the lowest level of measurement needed to calculate the mode?
nominal
As the size of samples (n) in a sampling distribution increases, the shape of that distribution becomes more...
normal
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
According to the central limit theorem when all possible samples of a sufficient size are taken from a bimodal population and their names are charted, that distribution of means will be...
normally distributed
As n increases, the point estimate for the mean will...
not change
Which measure requires a degrees of freedom calculation?
population variance
A distribution such as income that has most of the people at the bottom or middle but a few extremely high scores is referred to as
positively skewed
The amount of time a person spends on social media each week is a _______ variable.
ratio
If a researcher is using a critical value of +- 1.96 for a z-test and gets an observed z of -2.73, then the researcher should...
reject the null hypothesis
As the mean for a sample becomes greater, the width of the corresponding confidence interval will
stay the same
According to the central limit theorem the mean of the sampling distribution of means will equal...
the mean of the original population
If you conduct a one-sample z-test, you would test...
the null hypothesis of no difference between the groups mean and the population mean
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
A point estimate for the population mean is based on...
the sample mean
When calculating an effect size for the z-test
the sample size is irrelevant
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 sampling distribution of means
The standard error is...
the standard deviation of a sampling distribution
If a person were to create a sampling distribution for sample standard deviations then the mean of that distribution would be equal to...
the standard deviation of the original population
If the formula for the population standard deviation were used with sample data, then result would be...
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 low