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In: Statistics and Probability

The scores on a math test are normally distributed with a mean of 74 and a...

The scores on a math test are normally distributed with a mean of 74 and a standard deviation of 8. The test scores range from 0 to 100. Seven students had test scores between 82 and 98. Estimate the number of students who took the test.

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Expert Solution

µ =    74                              
σ =    8                              
we need to calculate probability for ,                                  
P (   82   < X <   98   )                  
=P( (82-74)/8 < (X-µ)/σ < (98-74)/8 )                                  
                                  
P (    1.000   < Z <    3.000   )                   
= P ( Z <    3.000   ) - P ( Z <   1.000   ) =    0.9987   -    0.8413   =    0.1573
...........

number of students who took the test = 7/0.1573

= 45 (approx)

.....................

THANKS

revert back for doubt

please upvote

orchestra answered 3 years ago
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