AP Statistics : Univariate Data
Study concepts, example questions & explanations for AP Statistics
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Example Questions
Example Question #1 : Univariate Data
Six homes are for sale and have the following dollar values in thousands of dollars:
535
155
305
720
315
214
What is the median value of the six homes?
The median is determined by ordering the values in the group from least to greatest: 155, 214, 305, 315, 535, 720. The value directly in the middle is the median. For instance, if there are five numbers, the third is the median. Here, we have an even number of values so there is no value directly in the middle. To find the median when there is no middle-most value, find the average of the two middle values. The mean is determined by adding the two values and dividing by two (the number in the group):
Example Question #1 : Data
Find the median of the set.
The median is the middle value of the set in increasing order.
In this set of 11 entries, the median is the 6th entry of the set in increasing order, or 6.
Example Question #1 : How To Find The Median For A Set Of Data
Find the median of the set
The median is the middle value of the set in increasing order.
In this set of 6 (or any even number of) entries, the median is the mean of the two middle entries of the set in increasing order
or
Example Question #2 : Univariate Data
Let 
Find the median of the set.
The median is the middle value of the set in increasing order.
In this set of 8 (or any even number) entries, the median is the mean of the two middle entries of the set in increasing order
or
Example Question #1 : Univariate Data
Suppose a basketball team plays six games and scores the following points: 69, 78, 82, 69, 98, 85. Find the median.
75.5
82
80
69
80
To find the median of a sample with an even sample size, order the values from smallest to largest, take the two values in the middle, add them, and divide that by zero.
69, 78, 82, 69, 98, 85
69, 69, {78, 82} 85, 98
(78+82) / 2 = 80
Example Question #1 : Data
A sample consists of the following observations:
The mean is
Example Question #3 : Univariate Data
A bird watcher observed how many birds came to her bird feeder for four days. These were the results:
Day 1: 15
Day 2: 12
Day 3: 10
Day 4: 13
What is the mean number of birds?
The mean is calculated by adding the values from the four days together, then dividing the sum by the total number of values. In this case, four values must be added:
Example Question #1 : How To Find The Mean For A Set Of Data
What is the mode of the following list of numbers?
35, 17, 4, 25, 7, 4, 17, 26, 8, 17
The mode is the number that appears most frequently in a series of numbers. First, organize the numbers in order from least to greatest: 4, 4, 7, 8, 17, 17, 17, 25, 26, 35. The number 17 appears three times, more than any other number.
Example Question #1 : Univariate Data
Find the mean of the following set.
To find the mean of a set, follow the formula
in this case
or
Example Question #3 : How To Find The Mean For A Set Of Data
A business tracked the number of customer calls received over a period of five days. What was the mean number of customer calls received in a day?
Day 1: 57
Day 2: 63
Day 3: 48
Day 4: 49
Day 5: 59
The mean is calculated by adding all the values in a data set, then dividing the sum by the total number in the group.
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