The gmac insurance company reported that the mean score on the national drivers test was 69.9 with a standard deviation of 3.3 points. the test scores are approximately bell-shaped. approximately 68% of all test scores were between two values a and b. what is the value of a? write only a number as your answer. round to one decimal place.

The value of A is 66.6.

Step-by-step explanation:

According to the Empirical rule ,

Approximately 68% of all data values lies within one standard deviation from the mean.

Given : The GMAC Insurance company reported that the mean score on the National Drivers Test was 69.9 with a standard deviation of 3.3 points.

The test scores are approximately bell-shaped.

Then , Approximately 68% of all test scores were between 69.9- 3.3 and 69.9+3.3.

i.e. Approximately 68% of all test scores were between 66.6 and 73.2 .

On comparing it to the statement, "Approximately 68% of all test scores were between two values A and B. "

Hence, the value of A is 66.6.