I took the practice exam 1 from TIA and I ran into a question with continuity correction. The question stated:

A fair 6-sided die is rolled 1,000 times. Using a normal approximation with a continuity correction, what is the probability that the number of 3's that are rolled is greater than 150 and less than 180.

Fairly simple question:

I calculated:

mean: 166.67 (1000/6)

Sx: 11.78 [sqrt (1000 *5/36)]

The continuity part however was the part I got "wrong".

The problem is, I believe I am right in that: to calculate the prob of rolling greater than 150 w/ a continuity correction is 149.5 where as the solution wrote 150.5. And less than 180 w/ a continuity correction as 180.5 instead of the solution of 179.5.

The entire point of the continuity correction is to include the number (in this case: 150 and 180) while calculating the probability because the normal distribution only calc. probability of < the specified number.

Please explain whether I am wrong or the solution? And if I am wrong...why?

A fair 6-sided die is rolled 1,000 times. Using a normal approximation with a continuity correction, what is the probability that the number of 3's that are rolled is greater than 150 and less than 180.

Fairly simple question:

I calculated:

mean: 166.67 (1000/6)

Sx: 11.78 [sqrt (1000 *5/36)]

The continuity part however was the part I got "wrong".

The problem is, I believe I am right in that: to calculate the prob of rolling greater than 150 w/ a continuity correction is 149.5 where as the solution wrote 150.5. And less than 180 w/ a continuity correction as 180.5 instead of the solution of 179.5.

The entire point of the continuity correction is to include the number (in this case: 150 and 180) while calculating the probability because the normal distribution only calc. probability of < the specified number.

Please explain whether I am wrong or the solution? And if I am wrong...why?

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