Jack usually mows his lawn in 3 hours. Marilyn can mow the same yard in 4 hours. How much time would it take for them to mow the lawn together? They could mow the lawn in \( \square \) hours if they worked together.

A calculator displays 5.449E-6. How do you write 5.449E-6 in standard form?

elen fills fruit bowis at a restaurant. She puts \( \frac{2}{3} \) pint of fruit in each bowl, How many bowis can Helen serve with 29

Graph the following polynomial function. \( f(x)=2 x^{3}+3 x^{2}+6 x+9 \)

Here are summary statistics for the weights of Pepsi in randomly selected cans: \( \mathrm{n}=36, \overline{\mathrm{x}}=0.82407 \mathrm{lb}, \mathrm{s}=0.00569 \mathrm{lb} \). Use a confidence level of \( 99 \% \) to complete parts (a) through (d) below. a. Identify the critical value \( \mathrm{t}_{\alpha / 2} \) used for finding the margin of error. \( \mathrm{t}_{\alpha / 2}=2.72 \) (Round to two decimal places as needed.) b. Find the margin of error. \( \mathrm{E}=\square \mathrm{lb} \) (Round to five decimal places as needed.)

A clinical trial was conducted to test the effectiveness of a drug for treating insomnia in older subjects. Before treatment, 18 subjects had a mean wake time of 103.0 min. After treatment, the 18 subjects had a mean wake time of 74.9 min and a standard deviation of 24.6 min. Assume that the 18 sample values appear to be from a normally distributed population and construct a \( 99 \% \) confidence interval estimate of the mean wake time for a population with drug treatments. What does the result suggest about the mean wake time of 103.0 min before the treatment? Does the drug appear to be effective? Construct the \( 99 \% \) confidence interval estimate of the mean wake time for a population with the treatment. 58.1 min < \( \mu<91.7 \) min (Round to one decimal place as needed.) What does the result suggest about the mean wake time of 103.0 min before the treatment? Does the drug appear to be effective? The confidence interval This result suggests that the drug treatment the mean wake time of 103.0 min before the treatment, so the means before and after the treatment