2. Suppose a consumer group suspects that the proportion of households that have three or more cell phones is 30%. A cell phone company has reason to believe that the proportion is not 30%. Before they start a big advertising campaign, they conduct a hypothesis test. Their marketing people survey 150 randomly selected households with the result that 43 of the households have three or more cell phones. Using a significance level of 10%, construct a hypothesis test to determine if the consumer group is correct and state your conclusion. Provide an interpretation in the context of this problem. 7 Accessibility: Investigate FOCUS DELL3. You do a study of hypnotherapy to determine how effective it is in increasing the number of hours of sleep subjects get each night. You measure hours of sleep for 12 randomly selected subjects with the following results. 8.2; 9.1; 7.7; 8.6; 6.9: 11.2; 10.1; 9.9; 8.9; 9.2; 7.5; 10.5 Construct a 95% confidence interval for the mean number of hours slept for the population ( assumed normal) from which you took the data. Provide an interpretation in the context of this problem. (4 pt) TX Accessibility: Investigate Focus 99 DELL4. It is believed that a stock price for a particular company will grow at an average rate of $5 per week with a standard deviation of $1. An investor believes the stock will grow less quickly per week. The changes in stock price are recorded for a random selection of ten weeks, are as follows: $4, $3, $2, $3, $1, $7, $2, $1, $1, $2. Perform a hypothesis test using a 5% level of significance. State the null and alternative hypotheses and state your conclusion. Provide an interpretation in the context of this problem. essibility: Investigate 199+ O O 5 DELL Insert