ISDS 361A Final Exam Concept Questions with
Answers
The collection of all units of interest in a particular study is called
a. Sample
b. Parameter
c. Population
d. Statistic - -Population
-Suppose there is a dataset of baseball scores from several matches between the Seattle
Mariners and
Anaheim Angels. A statistician wants to summarize the data using graphical and numerical
measures.
What branch of Statistics will she need to use?
a. Descriptive Statistics
b. Inferential Statistics - -Descriptive Statistics
-Which of these is not a measure of variability?
a. Mean
b. Standard deviation
c. IQR
d. Range - -Mean
-A histogram with a long left tail is said to be
a. Symmetric
b. Bell-shaped
c. Positively skewed
d. Negatively skewed - -Negatively skewed
-For a positively skewed distribution
a. Mean is smaller than median
b. Mean is equal to the median
c. Mean is greater than the median
d. None of the above - -Mean is greater than the median
-A standard normal distribution is one that has
a. Zero mean and zero variance
b. Zero mean and constant variance
c. Constant mean and variance = 1
d. Zero mean and variance = 1 - -Zero mean and variance = 1
-For a random variable X with mean = 10 and variance = 25, what is P(X > 20)?
a. P(Z > 2)
b. P(Z < 2)
, c. P(Z > 0.4)
d. P(Z > -0.4) - -P(Z > 2)
-Which theorem or rule helps determine the sampling distribution of the sample mean?
a. Chebyshev's Theorem
b. Central Limit Theorem
c. Empirical Rule
d. None of the above - -Central Limit Theorem
-How does the standard error of the sampling distribution behave as the sample size (n)
increases?
a. Decreases
b. Increases
c. Stays unchanged
d. Cannot be determined - -Decreases
-With an increase in the sample size (n), the confidence interval estimate of the population
mean gets
a. Wider
b. Narrower
c. Stays the same
d. Cannot be determined - -Narrower
-What is (1 - α) called in the context of statistical inference?
a. Significance level
b. Confidence level
c. Sample size
d. Standard error - -Confidence level
-What is the distribution of the test statistic for the hypothesis test of the population mean
when the
population standard deviation (σ) is unknown?
a. Normal distribution (z)
b. t-distribution with n degrees of freedom
c. t-distribution with n - 1 degrees of freedom
d. t-distribution with n - 2 degrees of freedom - -t-distribution with n - 1 degrees of
freedom
-We reject a null hypothesis (H0) when
a. The p-value is less than or equal to α
b. The p-value is greater than or equal to α
c. The p-value is equal to α
d. The p-value is not equal to α - -The p-value is less than or equal to α
-The point estimate of the difference between the two population means ( μ1 - μ2) is:
a. X1 - bar
Answers
The collection of all units of interest in a particular study is called
a. Sample
b. Parameter
c. Population
d. Statistic - -Population
-Suppose there is a dataset of baseball scores from several matches between the Seattle
Mariners and
Anaheim Angels. A statistician wants to summarize the data using graphical and numerical
measures.
What branch of Statistics will she need to use?
a. Descriptive Statistics
b. Inferential Statistics - -Descriptive Statistics
-Which of these is not a measure of variability?
a. Mean
b. Standard deviation
c. IQR
d. Range - -Mean
-A histogram with a long left tail is said to be
a. Symmetric
b. Bell-shaped
c. Positively skewed
d. Negatively skewed - -Negatively skewed
-For a positively skewed distribution
a. Mean is smaller than median
b. Mean is equal to the median
c. Mean is greater than the median
d. None of the above - -Mean is greater than the median
-A standard normal distribution is one that has
a. Zero mean and zero variance
b. Zero mean and constant variance
c. Constant mean and variance = 1
d. Zero mean and variance = 1 - -Zero mean and variance = 1
-For a random variable X with mean = 10 and variance = 25, what is P(X > 20)?
a. P(Z > 2)
b. P(Z < 2)
, c. P(Z > 0.4)
d. P(Z > -0.4) - -P(Z > 2)
-Which theorem or rule helps determine the sampling distribution of the sample mean?
a. Chebyshev's Theorem
b. Central Limit Theorem
c. Empirical Rule
d. None of the above - -Central Limit Theorem
-How does the standard error of the sampling distribution behave as the sample size (n)
increases?
a. Decreases
b. Increases
c. Stays unchanged
d. Cannot be determined - -Decreases
-With an increase in the sample size (n), the confidence interval estimate of the population
mean gets
a. Wider
b. Narrower
c. Stays the same
d. Cannot be determined - -Narrower
-What is (1 - α) called in the context of statistical inference?
a. Significance level
b. Confidence level
c. Sample size
d. Standard error - -Confidence level
-What is the distribution of the test statistic for the hypothesis test of the population mean
when the
population standard deviation (σ) is unknown?
a. Normal distribution (z)
b. t-distribution with n degrees of freedom
c. t-distribution with n - 1 degrees of freedom
d. t-distribution with n - 2 degrees of freedom - -t-distribution with n - 1 degrees of
freedom
-We reject a null hypothesis (H0) when
a. The p-value is less than or equal to α
b. The p-value is greater than or equal to α
c. The p-value is equal to α
d. The p-value is not equal to α - -The p-value is less than or equal to α
-The point estimate of the difference between the two population means ( μ1 - μ2) is:
a. X1 - bar
