For this problem I found the mean however I cannot seem to find the standard deviation. I tried everything for the formula to adding, subtracting, multiplying, dividing but still no correct answer. Can someone please help and explain how you got the answer?

Alawn mower manufacturer incurs a total of 34,816 in overhead costs and 388 per lawn mower in production costs. how many lawn mowers were manufactured if the average cost of productions is 660

The size of a certain cell is 2.5*10^-9m. another cell is 1.5*10^3 times larger. how large is the larger cell in scientific notation?

Formulate the indicated conclusion in nontechnical terms. be sure to address the original claim. the foundation chair for a hospital claims that the mean number of filled overnight beds is over 523, and she is therefore justified starting a funding campaign to add a wing to the hospital. assuming that a hypothesis test has been conducted and that the conclusion is failure to reject the null hypothesis, state the conclusion in nontechnical terms.