So, I know this question has been asked on here before but Ive read the explanations and still have not understood. I'm trying to teach myself this process because I do online math. However, math does not come easily to me so its been pretty difficult. Any help from anybody on the process of solving this problem would be greatly greatly appreciated. Thanks so much. :)

1.) The time required to finish a test is normally distributed with a mean of 60 minutes and a standard deviation of 10 minutes. What is the probability that a student will finish the test in less than 70 minutes?

Question

So, I know this question has been asked on here before but Ive read the explanations and still have not understood. I'm trying to teach myself this process because I do online math. However, math does not come easily to me so its been pretty difficult.  Any help from anybody on the process of solving this problem would be greatly greatly appreciated. Thanks so much. :)

1.) The time required to finish a test is normally distributed with a mean of 60 minutes and a standard deviation of 10 minutes. What is the probability that a student will finish the test in less than 70 minutes?

amistre64 · Answer

its an empirical rule assessment

what do you know about the empirical rule?

amistre64 · Answer

the empirical rule is an approximation of a normal standard probability curve

within +- 1 standard deviation from the mean, there lies about 68% of the data
within +- 2 standard deviation from the mean, there lies about 95% of the data
within +- 3 standard deviation from the mean, there lies about 99% of the data

amistre64 · Answer

with a mean of 60, and a standard deviation of 10;  70 is +1 standard deviations away from the mean:  60+10 = 70

amistre64 · Answer

all the values less then 70 is what we want to find .... we should know that anything up to the mean equates to 50% of the normal distribution,  so all thats left is to add in the missing percentage

amistre64 · Answer

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