Answers

1. Step-by-step explanation:

   we need to look up the p-value in the z-table.

   for z = 1.36 we get 0.91309.

   this is p(the population mean is less than 9).

   left-tailed test (less) : p-value = z-table(1.36)

   right-tailed test (larger) : p-value = 1 – z-table(1.36)

   two-tailed test (not equal to) :

   p-value = 2×minimum(z-table(1.36), 1 – z-table(1.36))

   (a) is clearly the left-tailed test.

   p-value (as above) = 0.91309

   (b) is clearly the two-tailed test.

   z-table(1.36) = 0.91309

   1 – z-table(1.36) = 1 – 0.91309 = 0.08691

   the minimum of these 2 values is 0.08691.

   so,

   p- value = 2×0.08691 = 0.17382

   FYI – in both cases that p- value is not small enough (typically it should be <= 0.05) to drop H0.

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