You are designing a marketing plan to reach teenagers and young adults. say the that in the population, the mean response of all teenagers is µt and the mean response of all young adults is µya. the target population is 40% teenagers and 60% young adults and thus our goal is to estimate 0.4µt + 0.6µya. you will do this by creating a focus group consisting of 100 people where 64 are teenagers and 36 are young adults. call x¯t the sample mean of these 64 teenagers in your focus group and x¯ya the sample mean of the 36 young adults in your focus group. a) create an estimate of the target population's response using these two sample averages. b) if the variance of the outcome is 4, what is the mse (mean squared error) of your estimate?