Question

1. The mean of a normally distributed data set is 112, and the standard deviation is 18.
   a) Use the Empirical Rule to find the probability that a randomly-selected data value is greater than 130.
   b) Use the Empirical Rule to find the probability that a randomly-selected data value is greater than 148.
   
   
2. A psychologist wants to estimate the proportion of people in a population with IQ scores between 85 and 130. The IQ scores of this population are normally distributed with a mean of 100 and a standard deviation of 15. Use the Empirical Rule to estimate the proportion.
   
   
3. The mean of a normally distributed data set is 112, and the standard deviation is 18.
   a) Use the standard normal table to find the probability that a randomly-selected data value is greater than 130.
   b) Use the standard normal table to find the probability that a randomly-selected data value is greater than 148.
   
   
4. A psychologist wants to estimate the proportion of people in a population with IQ scores between 85 and 130. The IQ scores of this population are normally distributed with a mean of 100 and a standard deviation of 15. Use the standard normal table to estimate the proportion.
   
   
5. Why are your answers to questions 8 and 9 not identical to your answers to questions 6 and 7, respectively?
   
   
6. The mean of a normally distributed data set is 112, and the standard deviation is 18.
   a) Use the standard normal table to find the probability that a randomly-selected data value is greater than 110.
   b) Use the standard normal table to find the probability that a randomly-selected data value is less than 100.
   

Answer 1