Tensile strength is the amount of stress a material can withstand before it breaks. Researchers wanted to determine the tensile strength of a resin cement used in bonding crowns to teeth. The researchers bonded crowns to 72 extracted teeth. Using a tensile resistance test, they found the mean tensile strength of the resin cement to be 242.2 newtons (N), with a standard deviation of 70.6 N. Based on this information, construct a 90% conﬁdence interval for the mean tensile strength of the resin cement.
Answer to relevant QuestionsTravelers pay taxes for ﬂying, car rentals, and hotels. The following data represent the total travel tax for a 3-day business trip in eight randomly selected cities. (a) Determine a point estimate for the population mean ...Treat the data obtained in the Sullivan Statistics Survey as a simple random sample of adult Americans. One question asked in the survey was “If you own a cell phone, what was your cell phone bill last month? Express ...A researcher wanted to determine the mean number of hours per week (Sunday through Saturday) the typical person watches television. Results from the Sullivan Statistics Survey indicate that s = 7.5 hours. (a) How many people ...The mean age of the 43 presidents of the United States (as of 2011) on the day of inauguration is 54.6 years, with a standard deviation of 6.3 years. A researcher constructed a 95% conﬁdence interval for the mean age of ...Based on a poll conducted by the Centers for Disease Control, 862 of 1013 randomly selected adults said that they always wear seat belts. Construct and interpret a 95% conﬁdence interval for the proportion of adults who ...
Post your question