Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

Safari File Edit View History Bookmarks Window Help Review Question 5 (of 60 sco

ID: 3200637 • Letter: S

Question

Safari File Edit View History Bookmarks Window Help Review Question 5 (of 60 score This Question 5. 10.00 points. Scores on the final in a statistics class are as follows. 75 25 75 62 80 85 80 99 90 60 86 92 40 74 72 65 87 70 85 70 Click here for the Excel Data File a. Calculate the 25th, 50th, and 75th percentiles. (Do not round intermediate calculations. Round your answers to 2 decimal places.) 25th percentile 50th percentile 75th percentile b-1. Select a box plot. x Plot B Box Plot A of scores MacBook Pro

Explanation / Answer

a.

The first quartile (or lower quartile or 25th percentile) is the median of the bottom half of the numbers. So, to find the first quartile, we need to place the numbers in value order and find the bottom half.

25   40   60   62   65   70   70   72   74   75   75   80   80   85   85   86   87   90   92   99   

So, the bottom half is

25   40   60   62   65   70   70   72   74   75   

The median of these numbers is 67.5.

The median is the middle number in a sorted list of numbers. So, to find the median, we need to place the numbers in value order and find the middle number.

Ordering the data from least to greatest, we get:

25   40   60   62   65   70   70   72   74   75   75   80   80   85   85   86   87   90   92   99   

As you can see, we do not have just one middle number but we have a pair of middle numbers, so the median is the average of these two numbers:

Median=75+75/2=75

The third quartile (or upper quartile or 75th percentile) is the median of the upper half of the numbers. So, to find the third quartile, we need to place the numbers in value order and find the upper half.

25   40   60   62   65   70   70   72   74   75   75   80   80   85   85   86   87   90   92   99   

So, the upper half is

75   80   80   85   85   86   87   90   92   99   

The median of these numbers is 85.5.

Hire Me For All Your Tutoring Needs
Integrity-first tutoring: clear explanations, guidance, and feedback.
Drop an Email at
drjack9650@gmail.com
Chat Now And Get Quote