Question

A local weather enthusiast wants to see if the last five summers have been warmer than normal for eloy, arizona. from the national oceanic and atmospheric administration (noaa), he knows the 30-year average for july was 90° with a standard deviation of 2.1°. the last five summers recorded have an average of 93.5°. if he uses a = 5%, which of the following would be valid based on the data he has gathered? he can conclude that the summers have been warmer than the 30-year average. he can conclude that the summers will continue to be warmer for the next 10 years. he does not have enough information to make a decision. the average for the last five years fits with the 30-year average.

Answer 1

For the local weather of Eloy, Arizona, the average for the last five years fits with the 30-year average.

What do you mean by standard deviation?

In statistics, Standard deviation is a measure of the variation of a set of values.

σ = standard deviation of a population

N = number of observations of population

X = mean

μ = population mean

The 30-year average for July was 90°. The standard deviation for this average is 2.1°. Thus, the temperature lies in the range around of 90° in July.

Therefore, the range of the temperature is,

t = 90 - 2.1 = 87.9

t = 90 + 2.1 = 92.1

The last five summers recorded have an average of 93. 5° and the value of a is 5%. Thus, the reduction is,

t = 92 - (92 x 2.5/100)

t = 89.70

This value of temperature lies in the range of 87.9-92.1 degrees Celsius. Hence, the two averages are probably the same.

Hence, for the local weather of Eloy, Arizona, the average for the last five years fits with the 30-year average. Option D is correct.

Learn more about the standard deviation here;

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