Download Standard Deviation Review HW 1

Name __________________________
Standard Deviation Review
1) If you have the variance, how do you get the standard deviation?
2) Calculate the Standard Deviation for the following data which was sampled from a large
population: 4,10,12,2,15,5
3) Why do you need a measure of variability?
a) to calculate the median
b) to describe how far the data is spread around the mean
c) to understand the highest and lowest data points
d) to calculate the mean
4) A standard deviation of 0 means?
a) all values are the same
b) you cannot have a standard deviation of 0
c) there is an extreme amount of variability
Name __________________________
d) you did the calculations wrong
Standard Deviation Review
1) If you have the variance, how do you get the standard deviation?
2) Calculate the Standard Deviation for the following data which was sampled from a large
population: 4,10,12,2,15,5
3) Why do you need a measure of variability?
a) to calculate the median
b) to describe how far the data is spread around the mean
c) to understand the highest and lowest data points
d) to calculate the mean
4) A standard deviation of 0 means?
a) all values are the same
b) you cannot have a standard deviation of 0
c) there is an extreme amount of variability
d) you did the calculations wrong
5) Find the standard deviation of 1, 2, 3, 4, 5.
6) A manufacturer of automobile batteries claims that the average length of life for its
grade "A" battery is 60 months. However the guarantee on this brand is just for 36 months.
Suppose the standard deviation of the life length is known to be 10 months, and frequency
distribution of the life-length is known to be normal. What percent of batteries will not
last though the guaranteed span of 36 months?
7) A normal distribution has a mean of 80 and a standard deviation of 14. Determine the
value above which 80% of values will occur?
8) A reading program is administered to the bottom 5% of the students. If the average
score of the students is 122.6, find the cutoff score that will make a student eligible to the
program. The standard deviation is 18 and we know that the variable is normally distributed.
5) Find the standard deviation of 1, 2, 3, 4, 5.
6) A manufacturer of automobile batteries claims that the average length of life for its
grade "A" battery is 60 months. However the guarantee on this brand is just for 36 months.
Suppose the standard deviation of the life length is known to be 10 months, and frequency
distribution of the life-length is known to be normal. What percent of batteries will not
last though the guaranteed span of 36 months?
7) A normal distribution has a mean of 80 and a standard deviation of 14. Determine the
value above which 80% of values will occur?
8) A reading program is administered to the bottom 5% of the students. If the average
score of the students is 122.6, find the cutoff score that will make a student eligible to the
program. The standard deviation is 18 and we know that the variable is normally distributed.