Managers at Matthew's Sporting Goods are concerned that the dumbbells from one of the store's new suppliers are poorly made. To investigate, the managers used a precision scale to weigh a random sample of 50 weights labeled "30 kg." They found that the dumbbells in the sample weighed an average of 30.1 kilograms, with a standard deviation of 3 kilograms. Find a 90% confidence interval for the mean weight of "30 kg" dumbbells manufactured by the new supplier.
Round your answers to the nearest tenth.

Acell phone company offers two plans to its subscribers. at the time new subscribers sign up, they are asked to provide some demographic information. the mean yearly income for a sample of 40 subscribers to plan a is $45,000 with a standard deviation of $9,200. for a sample of 25 subscribers to plan b, the mean income is $64,300 with a standard deviation of $7,100. at the 0.025 significance level, is it reasonable to conclude the mean income of those selecting plan b is larger? assume unequal population standard deviations. hint: for the calculations, assume the plan a as the first sample. what is the decision rule? (negative amount should be indicated by a minus sign. round your answer to 3 decimal places.) compute the value of the test statistic. (negative amount should be indicated by a minus sign. round your answer to 2 decimal places.) what is your decision regarding h0 ? reject h0 fail to reject h0 compute the p-value. less than 0.01 between 0.01 and 0.025 between 0.025 and 0.05 between 0.05 and 0.10 greater than 0.10