Probability

[neetusanjay]

Need help with below questions..

1.
Smalltown Elevator produces elevator rails. To meet specifications, an elevator rail must be between 0.995 inches and 1.005 inches in diameter. Suppose that the diameter of an elevator rail follows a normal random variable with mean of 1 inch and standard deviation of 0.003 inches. Rounded to the nearest one tenth of one percent, what fraction of all elevator rails will meet specifications?

90.4%
95.2%
93.4%
97.3%
None of the above

[Jim@StratusPrep]

would you mind breaking these up into different posts?

[[email protected]]

Hi neetusanjay,

These don't appear to be GMAT questions. If you're studying for the GMAT, then you won't see questions of this type.

GMAT assassins aren't born, they're made,
Rich

[Matt@VeritasPrep]

If if I remember my stats (it's been about eight years, so I'm not sure I'm right about any of these):

The first one is A (90.4%)
The second one is C (4.77%)
The third one is unclear - by number does the question mean "integer" or "real number"? Assuming this is for a continuous uniform distribution, you have f(x) = 1/(b-a) = 1/(100-0) = 1/100, or A (1%)

These are not even remotely GMAT questions, however.

[neetusanjay]

Thank you Matt. Really appreciate your response.