the weights of bats in a zoo are normally distributed with a mean of 2.2 pounds and a standard deviation of 0.3 pounds. about what percent of the bats at the zoo weigh between 2.2 pounds and 2.5 pounds?

95%
34%
68%

Question

the weights of bats in a zoo are normally distributed with a mean of 2.2 pounds and a standard deviation of 0.3 pounds. about what percent of the bats at the zoo weigh between 2.2 pounds and 2.5 pounds? 

95% 
34% 
68% <--- is this the answer?
14%

kirbykirby · Answer

Should be half of 68%

anonymous · Answer

So it would be 34%?
That's what. I got the first time but then I got 68% so I wasn't sure

kirbykirby · Answer

Yes 

When you standardize you get:
$$P\left(\frac{2.2-2.2}{0.3}<\frac{X-2.2}{0.3}<\frac{2.5-2.2}{0.3}\right)=P(0<Z<1)$$

So you're only looking from 0 to 1 standard deviation, not from -1 to 1 standard deviation (which is 68%)