Problem Set 2 238 individuals were enrolled in CSSS/SOC/STAT 221 during the Winter 2020 quarter and responded to the same anonymous survey that you completed at the beginning of the quarter. In this problem set, you will look at the relationship between the ages at which a random sample of these respondents received their first driver's license (ADL) and their first motor vehicle (AMV). Out of all 238 respondents, some opted not to respond to one or both questions: two individuals opted not to responded to either question, while four more provided ADL responses but not AMV. Additionally, 120 individuals either had not yet received their first license or their first vehicle, or both: 43 responded that they had not yet received their first driver's license and 116 individuals answered that they had not yet received their first motor vehicle. In this exercise, we will focus only on the population of students who reported the age at which they received their first driver's license (n = 188), omitting anyone who either chose not to answer the ADL question or who had not yet received their first driver license. The table on page 3 presents a stratified random sample drawn from the population of 168 students described above. Specifically, the sample was divided into two strata according to ADL: everyone who was "old" at first driver's license (i.e. greater than 16 years old) was coded as a 1, and everyone who was "young" (age 16 or younger) was coded as a 0. Out of the entire population, 103 were "young" and the other 85 were "old" at first driver's license. From each stratum of this indicator variable, 20 individuals were randomly selected and the age at which they received their first motor vehicle (AMV) is reported. For AMV, individuals who have never owned a motor vehicle are coded as '-1'; these responses should be treated as missing data and omitted from any calculation of summary statistics in the following problems. Also note that no human being has ever achieved a well-documented age greater than 122 years old, so any AMV value greater than this number should be regarded as invalid. In the following table, report the indexes ( i ) for the first and last valid case for each stratum (i.e., omitting all data with missing or unreasonably high AMV). Also calculate effective sample sizes ( 71 ) and the sample averages ( x ), sample variances ( s? ), sample standard deviations ( s ), and medians ( @, ) for stratum-specific AMV. Feel free to use the tables on page 4 to perform calculations of means, variances, and standard deviations