Suppose that a customer service center claims that the telephone calls it receives last 114 seconds on average, with a standard deviation of 9
seconds. If you took a sample of 324 telephone calls, which of the following
mean times would be within the 95% confidence interval?
A. 115.5 seconds
B. 114.5 seconds
C. 116.5 seconds
D. 117.5 seconds

Isee the amount was $90.00 then reduced to $75.00 , what is the percent ?

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.

Which expression is equivalent to (4 +6i)^2? ? -20 + 48i 8 + 12i 16 - 36i 20 + 48i