The mother of a teenager has heard a claim that 23​% of teenagers who drive and use a cell phone reported texting while driving. She thinks that this rate is too high and wants to test the hypothesis that fewer than 23​% of these drivers have texted while driving. Her alternative hypothesis is that the percentage of teenagers who have texted when driving is less than

The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive? (b) what is the probability that a randomly selected bag contains fewer than 1125 chocolate chips? (c) what proportion of bags contains more than 1225 chocolate chips? (d) what is the percentile rank of a bag that contains 1425 chocolate chips?

The value of cos 30° is the same as which of the following?

Simplify each expression. use positive exponents. show work . (x –2 y –4 x 3 ) –2