Question

The customer help center in your company receives calls from customers who need help with some of the customized software solutions your company provides. Previous studies had indicated that 20% of customers who call the help center are Hispanics whose native language is Spanish and therefore would prefer to talk to a Spanish-speaking representative. This figure coincides with the national proportion, as shown by multiple larger polls. You want to test the hypothesis that 20% of the callers would prefer to talk to a Spanish-speaking representative. You conduct a statistical study with a sample of 35 calls and find out that 11 of the callers would prefer a Spanish-speaking representative. The significance level for this test is 0.01. The value of the test statistic obtained is:

Answer 1

= x / n = 11 / 35 = 0.3143

Test statistic = z

= - P₀ / [P_{0 *} (1 - P₀ ) / n]

= 0.3143 - 0.2/ [(0.2 * 0.8) / 35]

= 1.69