1. Given a random variable X follows a Normal distribution with mean 10 and standard deviati
0.6827
2. Scores on a certain exam are normally distributed with a mean of 90 and a variance of 25.
99.8
3. A normal distribution is defined by two parameters, the mean and the
Standard Deviation
4. If for a certain x value in a normal distribution with mean equal to 4 the z-value is such that
Larger than 4
5. Suppose X is normally distributed with mean 50 and standard deviation 4. Find the probabili
0.9876
6. Suppose X is normally distributed with mean 20 and standard deviation 4, find the value x0
12.16
7. According to an NRF survey conducted by BIGresearch, the average family spends about $23
They spend less than $145 on back-to-college
electronics? They spend more than $340 on back-to-
college electronics?
They spend between $135 and $175 on back-to-college electronics?
8. According to the Air Transport Association of America, the average operating cost of an MD
At what operating cost would only 20% of the operating costs
be less? At what operating cost would 65% of the operating
costs be more?
What operating cost would be more than 85% of operating costs?
9. In a recent year, the average daily circulation of the Wall Street Journal was 2,276,207. Sup
On what percentage of days would circulation pass 1,790,000?
P (x > 1,790,000) 1
Suppose the paper cannot support the fixed expenses of a full-production
setup if the
P (x < 1,632,000)
0
10. Selection of the samples based on the convenience of the researcher is an example of
nonrandom sampling
