Researchers at the National Weather Center in the northeastern United States recorded the number of 90 degrees days each year since records first started in 1875. The numbers form a normal distribution with a mean of = 9.6 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 degrees days for the most recent n = 4 years and obtained M = 11.85. They want to know if the data indicates that the past four years have had significantly more 90 degrees days than would be expected for a random sample from this population.

What statistical test will you use?

Independent samples t-test

One-sample t-test

Regression

Correlation

Repeated measures t-test

z-test

One-way ANOVA

Then, answer why you picked the test you did?