Mr. Perez can get $5,000 with a probability of 0.4 or lose $2,000 with a probability of 0.6, if he inve in Ajax Company stock. What is your expected profit? What is the standard deviation of your profit

Mean and Standard Deviation. Assume that the random variable X is normally distributed, with mean =70 and standard deviation =16. Which of the following is the probability that X is less than 90?

PRACTICE ANOTHER   Recall that Benford's Law claims that numbers chosen from very large data files tend to have "1" as the first nonzero digit disproportionately often. In fact, research has shown that if you randomly draw a number from a very large data file, the probability of getting a number with "1" as the leading digit is about 0.301. Now suppose you are the auditor for a very large corporation. The revenue file contains millions of numbers in a large computer data bank. You draw a random sample of n = 225 numbers from this file and r = 85 have a first nonzero digit of 1. Let p represent the population proportion of all numbers in the computer file that have a leading digit of 1.   What is the value of the sample test statistic? (Round your answer to two decimal places.) ANSWER IS NOT 2.57   Find the P-value of the test statistic. (Round your answer to four decimal places.) ANSWER IS NOT 0.0102

4 decimal places

A probability Problems please experts help

Historical data show that customers who download music from a popular Web service spend approximately $22 per month, with a standard deviation of $3. Assume the spending follows the normal probability distribution. Find the probability that a customer will spend at least $19 per month. How much (or more) do the top 9% of customers spend? What is the probability that a customer will spend at least $19 per month? (Round to four decimal places as needed.) How much do the top 9% of customers spend? (Round to the nearest cent as needed.)