A pet food company is trialing a new brand of dog food, DoggeeDeLux, at two city supermarkets. The company thinks that there is a difference in how successfully supermarkets are selling their new brand. They think that, at Supermarket 1, the proportion of sales of DoggeeDeLux compared to all dog food sales at that supermarket is higher than the proportion of DoggeeDeLux sales compared to all dog food sales at Supermarket 2.

Say the true proportion of DoggeeDeLux sales over all dog food sales at supermarket 1 is p₁ and the true proportion of DoggeeDeLux sales over all dog food sales at supermarket 2 is p₂. The company's statistician conducts a test using the following pair of null and alternative hypotheses: H₀ : p₁ - p₂ = 0, H_a : p₁ - p₂ > 0.

The statistician takes a random sample of 60 people who purchase dog food from Supermarket 1 and 50 people who purchase dog food from Supermarket 2. The statistician is able to calculate a test statistic of 2.1 for the test of the difference in proportions.

Use the test statistic given to calculate the appropriate P-value for this test of hypothesis. Select the correct value from the list below. (Hint: remember to take account of whether a one-tailed or two-tailed test is being used.)

Select one:

a.0.036

b.0.041

c.0.021

d.0.018