Question: A sample of n = 16 employees’ productivity scores is selected from a normal distribution with a population mean μ = 80 and a population standard deviation σ = 6. Find the probability of obtaining a sample mean of employee productivity less than M = 78.

Answer Choices:
-1.33
.9082
1.5
.0918

Answer: .0918

Question: What is Step 2 in the process of conducting a hypothesis test?

Answer Choices:
Stating the hypotheses
Setting the criteria for a decision (to reject or not the hypothesis)
Collecting data and computing sample statistics
Making a decision

Answer: Stating the hypotheses

Question: Which of the following is NOT an assumption for hypothesis tests with z-scores?

Answer Choices:
Random sampling
Normal sampling distribution
Value of σ is unchanged by the treatment
Independent observations
Equal sample sizes in the treatment groups

Answer: Equal sample sizes in the treatment groups

Question: When conducting a hypothesis test, we evaluate the __________ by assuming that it is/are true and determining the plausibility of this assumption through the calculation of the probability of obtaining the results solely by chance.

Answer Choices:
alternative hypothesis
both the null and alternative hypothesis
standard error
null hypothesis

Answer: null hypothesis

Question: What decision should we make if, after calculating the test statistic, it does not fall within the critical region?

Answer Choices:
We should reject the null hypothesis.
We should not reject the alternative hypothesis.
We should reject the alternative hypothesis.
We should not reject the null hypothesis.

Answer: We should not reject the null hypothesis.

Question: On average, a certain population of patients with chronic conditions has a quality of life with a mean (μ) of 33 and a standard deviation (σ) of 6. It is hypothesized that exercise interventions affect the quality of life of these patients. What is the null hypothesis?

Answer Choices:
H1:μ≠33
H0:μ≠33
H1:μ=33
H0:μ=33

Answer: H0:μ=33

Question: In a hypothesis test, what is a Type I error?

Answer Choices:
Rejecting the null hypothesis when it is true
Failing to reject the null hypothesis when it is false (a false negative)
Rejecting the null hypothesis when it is true (a false positive)
Failing to reject the null hypothesis when it is false

Answer: Rejecting the null hypothesis when it is true (a false positive)

Question: This question is worth 3 points (most of the other questions are worth 1 point). To receive credit for this question, please ensure that you submit your calculations AND normal distribution sketch in the “Calculations Exam 2” document. Ensure that your calculations document includes the following: Calculation of the standard error. Computation of the z-core for the sample mean. Determination of the critical z-values for a two-tailed test with α = 0.1. On average, a certain population of patients with chronic conditions has a quality of life with a mean (μ) of 33 and a standard deviation (σ) of 12. It is hypothesized that exercise interventions affect the quality of life of these patients. After establishing your hypothesis and selecting a significance level α = 0.1, you gather sample data from 36 patients and calculate the mean quality of life as M = 36. Based on the computed sample statistics, make a decision regarding whether to reject or fail to reject the null hypothesis for this situation.

Answer Choices:
We should reject the alternative hypothesis.
We should not reject the null hypothesis.
We should reject the null hypothesis.
We should not reject the alternative hypothesis.

Answer: We should reject the null hypothesis.

Question: On average, a certain population of patients with chronic conditions has a quality of life with a mean (μ) of 33 and a standard deviation (σ) of 12. It is hypothesized that exercise interventions affect the quality of life of these patients. After establishing your hypothesis and selecting a significance level α = 0.1, you gather sample data from 36 patients and calculate the mean quality of life as M = 36. Based on the computed sample statistics, what of the following statements is accurate?

Answer Choices:
There is not enough evidence to suggest that exercise interventions have a significant effect on the quality of life of patients with chronic conditions.
If the effect of exercise interventions is uncertain, and further research is needed.
There is enough evidence to suggest that exercise interventions have a significant effect on the quality of life of patients with chronic conditions.

Answer: There is enough evidence to suggest that exercise interventions have a significant effect on the quality of life of patients with chronic conditions.

Question: If you add 5 to each score in a dataset, what will be the effect on the mean and standard deviation?

Answer Choices:
Mean increases, standard deviation increases.
Mean increases, standard deviation decreases.
Mean decreases, standard deviation increases.
Mean decreases, standard deviation decreases.
Mean increases, standard deviation stays the same.

Answer: Mean increases, standard deviation stays the same.

Question: What does it mean for a statistic to be unbiased?

Answer Choices:
It provides the most accurate estimate of a population parameter.
It provides a random estimate of a population parameter.
It measures the variability within a population parameter.
It is unaffected by the sample size.

Answer: It provides the most accurate estimate of a population parameter.

Question: How does an increase in sample variance affect the patterns in sample data?

Answer Choices:
It leads to more consistent patterns.
It decreases the variability of data patterns.
It leads to greater dispersion in data points.
It makes data patterns more predictable.

Answer: It leads to greater dispersion in data points.

Question: Why is it necessary to make a correction to the formulas for variance and standard deviation when computing these statistics for a sample?

Answer Choices:
The sample size is decreased as a result.
It takes into account the data’s outliers.
It corrects bias and accounts for degrees of freedom.
It simplifies the calculation process for easier computation.

Answer: It corrects bias and accounts for degrees of freedom.

Question: Calculate the sample variance for the following dataset: 5, 8, 10, 12, 15.

Answer: 11.6

Question: What is a z-score?

Answer Choices:
The number of standard deviations the actual score is above or below the mean.
The square root of the variance.
The raw score from a given data set.
The distance from the value of one variable based on the relationship with another variable.

Answer: The number of standard deviations the actual score is above or below the mean.

Question: What location in a distribution corresponds with z=-1.50?

Answer Choices:
Above the mean by a distance equal to 1.5 standard deviations
Below the mean by a distance equal to 1.5 standard deviations
Below the mean by a distance equal to 1.5 raw points
Above the mean by a distance equal to 1.5 raw points

Answer: Below the mean by a distance equal to 1.5 standard deviations

Question: Assuming we are looking at a population, if the mean is 25 and the standard deviation is 5, what is the z-score of X = 35?

Answer Choices:
2
-3
-2
3

Answer: 2

Question: For a sample with M=18 and s=3, what is the X-value corresponding with z= +2.00?

Answer Choices:
24
23
20
21

Answer: 24

Question: In a distribution of IQ scores with a mean = 105 and a standard deviation = 15, a score of X=120 would be transformed into z= +1.00. What does this mean?

Answer Choices:
X is the mean multiplied by one.
X is located above the mean by one standard deviation.
The mean is located above the X by one standard deviation.
The z-score is the same as the mean.

Answer: X is located above the mean by one standard deviation.