Question

1. The average stick of bubble gum is chewed for 7.2 minutes before being spit out. The Dentyne Chewing Gum company has conducted research, and believed it has developed a product that allows individual sticks of gum to be chewed for a longer time. A study of 425 gum chewers indicates a mean gum chewing time of 6.8 minutes with a standard deviation of 0.9 minutes. Is there statistical evidence that average chewing time for the new gum is different than what historic research says? Run the test at a 5% level of significance. z table

Step 1.           Set up hypotheses and determine level of significance

Step 2.             Select the appropriate test statistic

                                              

Step 3.             Set up decision rule

                                             

Step 4.            Compute the test statistic

                                          

Step 5.            Conclusion

Answer 1

Solution :

This is the two tailed test .

The null and alternative hypothesis is ,

H₀ :   = 7.2

H_a :    7.2

Test statistic = z

= ( - ) / / n

= (6.8 - 7.2) / 0.9 / 425

= -9.16

P(z < -9.16) = 0

P-value = 2 * 0 = 0

= 0.05

P-value <

Reject the null hypothesis .

There is sufficient evidence that average chewing time for the new gum is different than historic research .