Part 1

A chemistry student suweyed former students about how many different laboratory experiments they did that required use of a scale. The chemistry student found that a scale was required for experiments 20% of the time. The student had 13 laboratory experiments this semester. Assume that a scale being required for one laboratory experiment does not affect the likelihood of a scale being required for another laboratory experiment. Letx = the number of laboraton.r experiments this semester for which the student had to use a scale. (a) The random variable is which of the following? the number of experiments for which the student had to use a scale the number of students the number of times the student had a laboratory experiment the number of experiments for which the student did not have to use a scale {b} How many total laboratory experiments did the student have this semester? |:| (c) Determine whether the following statement is true or false. This scenario is an example of a binomial probability distribution. An engineering firm has designed a new type of battery that will hold a charge for more than 14 hours. It is known that 20% of the old type of batteries can hold a charge for more than 14 hours. (a) A simple random sample of 70 of the old type of batteries is drawn. Find the mean number of batteries that will hold a charge for more than 14 hours. (b) A simple random sample of 70 of the old type of batteries is drawn. Find the standard deviation of the number of batteries that will hold a charge for more than 14 hours. (Round your answer to two decimal places.) (c) A simple random sample of 70 of the new type of batteries is drawn. The success rate, p, for the new batteries is unknown. For which value of p will the standard deviation of the number of batteries holding a charge for more than 14 hours be greatest? O 0.50 O 0.40 O 0.30 O 0.20