Sampling Method Assignment
6 Pages1773 Words534 Views
Added on 2019-11-08
Sampling Method Assignment
Added on 2019-11-08
ShareRelated Documents
1.Identify the sampling method for each scenario. (a)An orchard farmer subdivides his orchard into 40 parcels of land. He randomly selects 4 parcels and inspects every tree on those parcels for the presence of a particular fungus. (b)A librarian inspects every fifth book on a shelf starting with the second to determine the number of items missing bar codes.(c)A hotel leaves customer satisfaction cards in each guestroom. At the end of the week, the general manager reads all 60 cards that were filled out by guests that week. (d)The College of Engineering randomly selects samples from each of its four branches (mechanical, civil, chemical, electrical) to assess the effectiveness of a new program for student advising2.If thecity council were to collect data on household incomes for its district, one would typically find the distribution to be skewed right. (a)Sketch a histogram that shows a skewed-right distribution. (b)If we are given the values $43,000 and $62,000, which is probably the mean and which is the median? Explain. This is a cluster sampling methodThis is a systematic samplingmethod This is censusThis is a stratified sampling methodSince the distribution is right-skewed $62,000 is probably the mean and $43,000 is probably the median. In a right-skewed distribution, the mean is normally larger than the median.
3.SAT Math scores tend to follow a bell-shaped distribution with a mean of 515 points and a standard deviation of 114 points. (a)What percent of SAT Math scores is less than 629? (b)What percent of SAT Math scores is between 401 and 743? (c)Any student whoseSAT Math score falls in the bottom 2.5% of allscores is immediately disqualifiedfrom considerationfor admission to State U. What is the cut-off score forthe lowest 2.5% of all scores?We begin by computing the z-scorez= ́x−μσ=629−515114=1P(z<1)=0.8413Thus the percent of SAT Math score that is less than 629 is 84.13%We begin by computing the z-scorez= ́x−μσ=743−515114=2z= ́x−μσ=401−515114=−1P(−1<z<2)=0.8185Thus the percent of SAT Math scores is between 401 and 743 is 81.85%We begin by computing the z-scoreThe z-score equivalent to the cumulative probability of0.025 (2.5%) is -1.959964Z = --1.959964z= ́x−μσ=x−515114=−1.959964x−515=−1.959964∗114x=(−1.959964∗114)+515=291.564Thus the cut-off is SAT Math scores less than 292
4.Consider the following data collected from a sample of 12 American black bears:Length (cm)139138139120.5149141141150166151.5129.5150Weight (kg)110609060851009585155140105110(a)Sketch a scatterplot of the data. Treat length as the explanatory variable. Describe the association. (b)Construct the equation for the line of best fit. Round your values to 3 decimal places. Length (cm)Weight (kg)xyX2Y21391101529019321121001386082801904436001399012510193218100120.560723014520.253600149851266522201722514110014100198811000014195133951988190251508512750225007225166155257302755624025151.51402121022952.2519600129.510513597.516770.25110251501101650022500121001714.51195173257.5246447.8127625
End of preview
Want to access all the pages? Upload your documents or become a member.