1. Assume the time a half hour soap opera has an average of
10.4 minutes of commercials. Assume the number of minutes of
commercials follows a normal distribution with standard deviation
of 2.3 minutes.
a. Find the probability a half hour soap opera has between 10
and 11 minutes of commercials. [Give three decimal places]
b. The lowest 10% of minutes of commercials is at most how
long? (In other words: find the maximum minutes for the lowest 10%
of number of minutes of commercials.) [Give three decimal
places]
2. Assume X follows a normal distribution with mean 5 and
standard deviation 2.
a. x=4 is how many standard deviations away from the mean.
Give answer with appropriate positive/negative sign.
3. Find the alpha value associated with z subscript alpha =
2.326
4. Assume random variable X follows a normal distribution with
mean 50 and standard deviation of 10.
Use the Empirical Rule to find P(30 < X < 60).
***Challenging*** Write as a probability, not as a percentage.
[Give three decimal places.]