The proportion p of residents in a community who recycle has traditionally been 60%. A policy maker claims that the proportion is less than 60% now that one of the recycling centers has been relocated. If 116 out of a random sample of 220 residents in the community said they recycle, is there enough evidence to support the policy maker's claim at the 0.10 level of significance? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) (a) State the null hypothesis H_0 and the alternative hypothesis H_1. (b). Determine the type of test statistic to use: z, t, chi-square, f. (c). Find the value of the test statistic. (Round to three or more decimal places.) (d). Find the critical value. (Round to three or more decimal places.) (e). Is there enough evidence to support the policy maker's claim that the proportion of residents who recycle is less than 60%? Yes No
Question
The proportion p of residents in a community who recycle has traditionally been 60%. A policy maker claims that the proportion is less than 60% now that one of the recycling centers has been relocated. If 116 out of a random sample of 220 residents in the community said they recycle, is there enough evidence to support the policy maker's claim at the 0.10 level of significance?
Perform a one-tailed test. Then complete the parts below.
Carry your intermediate computations to three or more decimal places. (If necessary, consult a list of formulas.) (a) State the null hypothesis H_0 and the alternative hypothesis H_1. (b). Determine the type of test statistic to use: z, t, chi-square, f. (c). Find the value of the test statistic. (Round to three or more decimal places.) (d). Find the critical value. (Round to three or more decimal places.) (e). Is there enough evidence to support the policy maker's claim that the proportion of residents who recycle is less than 60%? Yes No
Solution
(a) The null hypothesis H_0 is that the proportion of residents who recycle is still 60% (p = 0.60). The alternative hypothesis H_1 is that the proportion of residents who recycle is less than 60% (p < 0.60).
(b) The type of test statistic to use is z, because we are dealing with proportions.
(c) To find the value of the test statistic, we first need to calculate the sample proportion (p̂) and the standard error (SE). The sample proportion is 116/220 = 0.527. The standard error is sqrt[(0.60 * (1 - 0.60)) / 220] = 0.033. The z-score is then (0.527 - 0.60) / 0.033 = -2.212 (rounded to three decimal places).
(d) The critical value for a one-tailed test at the 0.10 level of significance is -1.282 (rounded to three decimal places). This is found on a standard z-table.
(e) Since the test statistic (-2.212) is less than the critical value (-1.282), we reject the null hypothesis. Therefore, there is enough evidence to support the policy maker's claim that the proportion of residents who recycle is less than 60%. So, the answer is Yes.
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