Three local districts are “swing” districts for an upcoming election on a contentious political issue. A survey will be conducted in which voters will be asked to rate their opinion regarding this issue on a scale of 0 (strongly oppose) to 10 (strongly support). A small preliminary random sample from each district was used to estimate the sample standard deviation s of responses for the district. The following table shows the number of voters N in each district and the sample standard deviation s of strength of support in each district.

We have a total population of 5332 voters and 3 strata (districts). The group doing the survey has enough funding to obtain a random sample of m = 250 total responses from all the districts.

(a) Compute the size of the random samples n₁, n₂, n₃ to taken from each district. Round each sample size to the nearest whole number and make sure they add up to m = 250.

(b) Suppose you took the appropriate random samples from each district and you got the following average political support measures (scale 0 to 10): x̅₁ = 6.2, x̅₂ = 3.1 x̅₃ = 8.5. Compute your best estimate for the population mean m (scale 0 to 10) of voter support for the issue from the total population of these three districts.

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District 1 District 2 District 3 N3 = 2890 s3 = 3.3 N2 = 917 s2 = 1.4 . Ni = 1525 s1 = 2.2 ...