Researchers at the National Weather Center recorded the number of 90-degree days each year. The numbers form a normal shaped distribution with a mean of = 9. and a standard deviation of = 1.9.

To see if the data showed any evidence of global warming, they also

computed the mean number of 90-degree days for the most recent n = 4 years and obtained M = 12.25 . Do the data indicate that the past four years have had significantly more 90-degree days than would be expected for a random sample from this population? Use a one-tailed test with

= .05.