Help with statistics test?

K

Koopa Troopa

New member
i need to know if i got this one question righton a test: The mean score on a test is 60 and variance 25. What is the probability that the randomly selected score is at least two standard deviations above the mean?
First off, i dont think we needed the mean for that specific part of the question since there was a part b and c asking for percentages that scores were between 45 and 65 where the mean was actually used.
i looked at my z-chart for standard normal distributions under -2.0 (2 std deviations) and came up with .0228 is this right?
 
2 SD is the 95% confidence interval. 5% of the results are outside the interval. 2.5% are above the mean,and 2.5% are below.

0228 is the more accurate answer.

Do you have MS Excel? If you do play around with these functions and you won't need that old table any more.

normdist
normsdist
normsinv
norminv
 
2 SD is the 95% confidence interval. 5% of the results are outside the interval. 2.5% are above the mean,and 2.5% are below.

0228 is the more accurate answer.

Do you have MS Excel? If you do play around with these functions and you won't need that old table any more.

normdist
normsdist
normsinv
norminv
 
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