3. (5 points) A company wishes to estimate the mean monthly electric bill. If the standard
deviation is $400, how large a sample is required to estimate the mean electric bill to within $100
with 98% confidence?

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

Find the number of positive three-digit even integers whose digits are among 9, 8, 7,5, 3, and 1.

What are the soultion(s) to the quadratic equation 40- x^2=0