WGU C955 APPLIED PROBABILITY AND STATISTICS FINAL EXAM QUESTIONS AND ANSWERS ALREADY
GRADED A+. 100% VERIFIED SOLUTIONS | UPDATED PER LATEST GUIDELINES | GRADED A+
Question 1
A researcher is studying the relationship between hours of sleep and test scores. Which type of graph would be
most appropriate to display this relationship?
A. Pie chart
B. Bar graph
C. Scatterplot
D. Histogram
🟢 Correct Answer:
C. Scatterplot
🔴 RATIONALE:
A scatterplot is used to display the relationship between two quantitative variables. It allows the researcher to
visualize the pattern of the data, including the direction, form, and strength of the relationship. A pie chart is
used for categorical data; a bar graph is for comparing categorical data; and a histogram is for displaying the
distribution of a single quantitative variable.
Question 2
What is the median of the following data set: 4, 8, 6, 10, 12?
,A. 6
B. 8
C. 10
D. 12
🟢 Correct Answer:
B. 8
🔴 RATIONALE:
To find the median, the data must first be arranged in ascending order: 4, 6, 8, 10, 12. The median is the middle
value, which is 8. The mean is 8 as well, but the median is the middle number in an ordered set.
Question 3
A researcher wants to determine the average age of all students at a university. Which term describes this
average age?
A. Statistic
B. Parameter
C. Variable
D. Constant
🟢 Correct Answer:
B. Parameter
🔴 RATIONALE:
A parameter is a numerical measure that describes a characteristic of an entire population. Since the researcher
,is interested in the average age of all students (the entire population), this is a parameter. A statistic describes a
characteristic of a sample. A variable is a characteristic that can take on different values, and a constant is a fixed
value.
Question 4
The probability of an event occurring is 0.75. What is the probability of the event not occurring?
A. 0.25
B. 0.50
C. 0.75
D. 1.00
🟢 Correct Answer:
A. 0.25
🔴 RATIONALE:
The sum of the probabilities of an event and its complement (the event not occurring) is always 1. Therefore,
the probability of the event not occurring is 1 - 0.75 = 0.25. This is a fundamental rule of probability.
Question 5
Which of the following is a measure of central tendency?
A. Standard deviation
B. Variance
, C. Median
D. Range
🟢 Correct Answer:
C. Median
🔴 RATIONALE:
Measures of central tendency describe the center of a data set. The mean, median, and mode are all measures
of central tendency. Standard deviation, variance, and range are measures of dispersion or spread, which
describe how the data are distributed around the center.
Question 6
A data set has a mean of 50 and a standard deviation of 5. What is the z-score for a data point of 60?
A. 1
B. 2
C. -2
D. 0.5
🟢 Correct Answer:
B. 2
🔴 RATIONALE:
The z-score is calculated using the formula: z = (x - μ) / σ, where x is the data point, μ is the mean, and σ is the
standard deviation. In this case, z = (60 - 50) / 5 = = 2. A z-score of 2 indicates that the data point is 2
standard deviations above the mean.
GRADED A+. 100% VERIFIED SOLUTIONS | UPDATED PER LATEST GUIDELINES | GRADED A+
Question 1
A researcher is studying the relationship between hours of sleep and test scores. Which type of graph would be
most appropriate to display this relationship?
A. Pie chart
B. Bar graph
C. Scatterplot
D. Histogram
🟢 Correct Answer:
C. Scatterplot
🔴 RATIONALE:
A scatterplot is used to display the relationship between two quantitative variables. It allows the researcher to
visualize the pattern of the data, including the direction, form, and strength of the relationship. A pie chart is
used for categorical data; a bar graph is for comparing categorical data; and a histogram is for displaying the
distribution of a single quantitative variable.
Question 2
What is the median of the following data set: 4, 8, 6, 10, 12?
,A. 6
B. 8
C. 10
D. 12
🟢 Correct Answer:
B. 8
🔴 RATIONALE:
To find the median, the data must first be arranged in ascending order: 4, 6, 8, 10, 12. The median is the middle
value, which is 8. The mean is 8 as well, but the median is the middle number in an ordered set.
Question 3
A researcher wants to determine the average age of all students at a university. Which term describes this
average age?
A. Statistic
B. Parameter
C. Variable
D. Constant
🟢 Correct Answer:
B. Parameter
🔴 RATIONALE:
A parameter is a numerical measure that describes a characteristic of an entire population. Since the researcher
,is interested in the average age of all students (the entire population), this is a parameter. A statistic describes a
characteristic of a sample. A variable is a characteristic that can take on different values, and a constant is a fixed
value.
Question 4
The probability of an event occurring is 0.75. What is the probability of the event not occurring?
A. 0.25
B. 0.50
C. 0.75
D. 1.00
🟢 Correct Answer:
A. 0.25
🔴 RATIONALE:
The sum of the probabilities of an event and its complement (the event not occurring) is always 1. Therefore,
the probability of the event not occurring is 1 - 0.75 = 0.25. This is a fundamental rule of probability.
Question 5
Which of the following is a measure of central tendency?
A. Standard deviation
B. Variance
, C. Median
D. Range
🟢 Correct Answer:
C. Median
🔴 RATIONALE:
Measures of central tendency describe the center of a data set. The mean, median, and mode are all measures
of central tendency. Standard deviation, variance, and range are measures of dispersion or spread, which
describe how the data are distributed around the center.
Question 6
A data set has a mean of 50 and a standard deviation of 5. What is the z-score for a data point of 60?
A. 1
B. 2
C. -2
D. 0.5
🟢 Correct Answer:
B. 2
🔴 RATIONALE:
The z-score is calculated using the formula: z = (x - μ) / σ, where x is the data point, μ is the mean, and σ is the
standard deviation. In this case, z = (60 - 50) / 5 = = 2. A z-score of 2 indicates that the data point is 2
standard deviations above the mean.
