Question

You are interested in testing Chips Ahoy’s claim that bags of Chips Ahoy cookies contain more than 1000 chips, on average. Suppose you have an SRS of 62 bags of cookies and find that the sample mean is 1022 chips. The sample standard deviation s is 94.2 chips. There are no outliers or signs of strong skew. (a) Check the conditions for inference. Are the data from an SRS? Are the sample size and distributional requirements met? Specify why or why not. (b) Construct a 95 percent confidence interval and provide a complete interpretation of the result. (c) Now you want to test the claim that bags of Chips Ahoy cookies contain more than 1000 chips on average. Begin by writing the null and alternative hypotheses in formal notation. (d) Now draw a picture of the sampling distribution. Label the mean under the null hypothesis. Label the sample mean. Shade the area that gives the P-value. (e) Calculate the test statistic, degrees of freedom for the test, and the range of P-values suggested by Table C. (f) Interpret the P-value. (g) Are the results significant at the α = 0.05 level? State your conclusion about the null and alternative hypotheses.

Answer 1