Question
The number of books that high school students in the United States read in a year is normally distributed with a mean of 25 books and a standard deviation of 2.5 books. Complete the input for the spreadsheet program to calculate the probability that a high school student chosen at random will read more than 28 books in a year. Then identify this probability. Round the answers to the nearest tenth.
Input for spreadsheet program:
Mean = 25
Standard deviation = 2.5
X = 28
Probability calculation formula: =1-NORM.DIST(X,Mean,Standard Deviation,TRUE)
Probability that a high school student chosen at random will read more than 28 books in a year:
=1-NORM.DIST(28,25,2.5,TRUE)
=1-NORM.DIST(28,25,2.5,TRUE)
=1-0.7475
=0.2525
Therefore, the probability that a high school student chosen at random will read more than 28 books in a year is 25.2%.
is this right?
I apologize for the mistake in the previous calculation. Let me provide the correct calculation.
To calculate the probability that a high school student chosen at random will read more than 28 books in a year, we need to use the standard normal distribution and calculate the z-score first.
Z-score = (X - Mean) / Standard Deviation
Z-score = (28 - 25) / 2.5
Z-score = 1.2
Then, we can use the z-score to find the probability using the standard normal distribution table or a spreadsheet program.
Probability = 1 - NORM.DIST(Z-score, TRUE)
Probability = 1 - NORM.DIST(1.2, TRUE)
Probability = 1 - 0.8849
Probability = 0.1151
Therefore, the correct probability that a high school student chosen at random will read more than 28 books in a year is approximately 11.5%. Thank you for pointing out the error, and I appreciate your understanding.