- A manufacturer of automobile batteries (#2988)
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 ...
statistics, standard deviation
- A normal distribution has a mean (#3515)
A normal distribution has a mean of 80 and a standard deviation of 14...
standard deviation, statistics, mean, normal distribution
- A pediatrician`s records show (#3038)
A pediatrician's records show that height of a random sample 25 girls at age 12 months to be 29.530 inches with a standard deviation of 1.0953 ...
statistics, standard deviation, variance
- A reading program is administered (#2948)
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 ...
normal distribution, statistics, standard deviation
- A whole sale distributor has found (#3310)
A whole sale distributor has found that the amount of a customer's order is a normal random variable with a mean of $200 and a standard deviation of $50...
standard deviation, statistics
- At a fair, 37 pumpkins were entered for judging (#3489)
At a fair, 37 pumpkins were entered for judging under the normal pumpkin division. If the masses are normally distributed and the average weight is 12.4 kg, with a standard deviation for 2.31 kg. What is the probability that a pumpkin has a mass between 13...
standard deviation, statistics, normal distribution
- Find the IQ score separating the top (#1404)
Find the IQ score separating the top 85% from the ...
statistics, probability, standard deviation, normal distribution, mean
- If the life, in years, of a washing machine (#2430)
If the life, in years, of a washing machine is normally distributed with a mean of 20 years and a standard deviation of 1.5 ...
standard deviation, statistics
- In a class of 25 students (#2972)
In a class of 25 students, the grades were normally distributed with a mean of 78 and a standard deviation of 5. Sketch the normal curve for the distribution. What percentage of the students scored above an 88...
normal distribution, statistics, mean, standard deviation
- In France, years of life expectancy (#3345)
In France, years of life expectancy are normally distributed with a mean of 81 years and a standard deviation fo seven years. For the French population:
a) What is the probability of living 92 years or ...
statistics, normal distribution, probability, standard deviation
- In Prof. Smith`s management course (#3363)
In Prof. Smith's management course the correlation between the students' total score before the final examination and their final examination scores is r=.06. The pre-exam totals for all students in the class have mean 280 and standard deviation of 30. The final exams scores have mean of 75 and standard deviation of 8. Prof Smith lost Suee's final exam but knows that her total before the esam was 300...
statistics, standard deviation
- Test for high school students (#2909)
Test for high school students with a 3.50 to 4.00 grade point average were normally distributed, with a mean of 38.8 and a standard diviation of 1.9. A student with a 3.5 to 4.00 grade point average who took the standarized tes is randomly ...
mean, normal distribution, standard deviation, statistics, probability
- The mean amount of time that a manager spends (#3058)
The mean amount of time that a manager spends in annual performance review with an employee is 27.2 minutes, with a standard deviation of 4.9 minutes. What percentage of the annual performance reviews in the department take between 22.3 and 32.1 minutes? Between 17.4 and 37 minutes? Between 12.5 and 41.9 ...
statistics, standard deviation
- With a height of 69 inches, Alexander was the shortest (#3097)
With a height of 69 inches, Alexander was the shortest president of a particular club in the past century. The club presidents of the past century have a mean height of 75.4 inches and a standard deviation of 2.7.
a. What is the difference between Alexander's height and the mean?
...
standard deviation, statistics, mean
