1.
Find the mean of the data below.
7, 23, 11, 32, 9
Correct Answer
B. 16.4
Explanation
The mean is calculated by adding up all the numbers in the data set and then dividing by the total number of values. In this case, the sum of the numbers is 7 + 23 + 11 + 32 + 9 = 82. Since there are 5 numbers in the data set, the mean is 82 divided by 5, which equals 16.4.
2.
If a data set has an outlier, which measure of central tendency would be the best measure of the middle to use?
Correct Answer
B. Median
Explanation
When a data set has an outlier, the best measure of central tendency to use is the median. The median is the middle value of a data set when it is arranged in ascending or descending order. Unlike the mean, which is greatly influenced by outliers, the median is not affected by extreme values. Therefore, it provides a more accurate representation of the middle value in a data set that contains outliers. The mode is not applicable in this case since it represents the most frequently occurring value, and the range only provides information about the spread of the data.
3.
Which of the following statements is NOT true about the two data sets below?
Set A: 156, 175, 122, 141, 178, 111 147.17 148.5
Set B: 189, 210, 167, 100, 125, 143 155.67 155
Correct Answer
A. The mean for Set A is approximately 9 more than Set B.
Explanation
The mean for Set A is not approximately 9 more than Set B because the mean for Set A is 147.17 and the mean for Set B is 155.67. The difference between the two means is approximately 8.5, not 9.
4.
Which data set has a larger spread in the top 25%?
Joy: 52, 67, 73, 81, 83, 89, 93
Chrystal: 68, 72, 73, 79, 84, 85
Jacob: 72, 75, 78, 81, 85, 89, 98
Sasha: 88, 89, 92, 95, 95, 96, 100
Correct Answer
C. Jacob
Explanation
Jacob has a larger spread in the top 25% because his data set includes the highest values among all the given data sets. The top 25% of Jacob's data set includes the values 85, 89, and 98, which are higher than any values in the other data sets. Therefore, Jacob's data set has a larger spread in the top 25%.
5.
Your county is conducting a survey to determine the mean annual income per household. Which of the following sampling methods would be more likely to result in a representative sample?
Correct Answer
C. Survey's sent to 100 homes that were randomly selected from a database of all county adults.
Explanation
A survey sent to 100 homes that were randomly selected from a database of all county adults would be more likely to result in a representative sample because it ensures that every adult in the county has an equal chance of being selected. This method helps to minimize bias and increase the likelihood that the sample accurately represents the entire population. The other options, such as a phone survey during a specific time frame or surveys sent to single-family homes, may introduce selection bias and may not accurately reflect the entire population.
6.
Find the MAD for the data set below.
18, 15, 24, 12, 29, 31, 24, 19, 27
Correct Answer
C. 5.43
Explanation
The mean absolute deviation (MAD) is a measure of the dispersion or spread of a data set. It is calculated by finding the absolute difference between each data point and the mean of the data set, and then taking the average of these differences. In this case, the given data set is 18, 15, 24, 12, 29, 31, 24, 19, 27. To find the MAD, we first calculate the mean of the data set, which is 22.1. Then, we find the absolute difference between each data point and the mean: |18-22.1|, |15-22.1|, |24-22.1|, |12-22.1|, |29-22.1|, |31-22.1|, |24-22.1|, |19-22.1|, |27-22.1|. Taking the average of these absolute differences, we get 5.43. Therefore, the MAD for this data set is 5.43.
7.
Which of the following is NOT an example of a measure of central tendency?
Correct Answer
B. Range
Explanation
The range is not an example of a measure of central tendency because it measures the dispersion or spread of data rather than its central value. Measures of central tendency, such as the mean, median, and mode, are used to describe the typical or central value of a dataset. The range, on the other hand, simply calculates the difference between the maximum and minimum values in the dataset, providing information about the variability or spread of the data points.
8.
What does percentile do?
Correct Answer
C. Divides the set into 100 equal parts
Explanation
Percentile is a statistical measure that divides a set of data into 100 equal parts. It represents the percentage of values below a certain point in the data set. For example, if a student scores in the 80th percentile on a test, it means that their score is higher than 80% of the other scores. Therefore, the correct answer is "Divides the set into 100 equal parts."
9.
How can you find the value of mode graphically?
Correct Answer
A. Histogram
Explanation
A histogram is a graphical representation of data that uses bars to represent the frequency or count of different categories or intervals. The mode is the value or category that appears most frequently in the data. By examining the heights of the bars in a histogram, we can determine which category or interval has the highest frequency, thus identifying the mode graphically. Therefore, a histogram is a suitable tool for finding the value of mode graphically.
10.
To calculate the median correctly, what must be done?
Correct Answer
C. Arrange all the data in an ascending or descending order
Explanation
To calculate the median correctly, it is necessary to arrange all the data in an ascending or descending order. This is because the median is the middle value of a dataset when it is ordered. By arranging the data in a specific order, it becomes easier to identify the middle value and accurately calculate the median. Arranging the data in random order or adding all the data would not provide the correct result for calculating the median.