Question

The Specific Absorption Rate (SAR) for a cell phone measures the amount of radio frequency (RF) energy absorbed by the user's body when using the handset. Every cell phone emits RF energy. Different phone models have different SAR measures. To receive certification from the Federal Communications Commission (FCC) for sale in the United States, the SAR level for a cell phone must be no more than 1.4 watts per kilogram. A sample of 50 models was tested and the average of their Specific Absorption Rates (SAR) was found to be 1.18 watts per kilogram. Assume that the population standard deviation is 0.25 watts per kilogram Construct a 99% confidence interval for the mean of the SARS for cell phones that received certification from FCC. 1. Procedure: One mean Z procedure ii. Assumptions: (select everything that applies) Population standard deviation is unknown Normal population Population standard deviation is known Sample size is greater than 30 The number of positive and negative responses are both greater than 10 Simple random sample ii. Unknown parameter: H. population mean iv. Point estimate: sample mean, X watts per kilogram (Round the answer to 2 decimal places) v. Confidence level % and a = and 1 - Critical values: (Round the answer to 2 decimal places) also 2 left- Hint: For any distribution X, the right critical value is tą. right- vi. Margin of error (if applicable): (Round the answer to 2 decimal places) vii. Lower bound: (Round the answer to 2 decimal places) viii. Upper bound: (Round the answer to 2 decimal places) ix. Confidence interval: x. Interpretation: We are % confident that the mean of the SARS for cell phones that received certification from FCC is between watts per kilogram and watts per kilogram. Based on the confidence interval, is it reasonable to believe that the mean of the SARS for cell phones that received certification from FCC is greater than 1.4 watts per kilogram? Explain. Nov because a part or the entire interval is below O 1.4 watts per kilogram.

Answer 1

(ii) Normal population

Population standard deviation is known

Sample size is greater than 30

Simple random sample

(iv) 1.18

(v) 99, 0.01

0.005, 0.995

left = -2.58

right = 2.58

(vi) 0.09

(vii) 1.09

(viii) 1.27

(ix) (1.09, 1.27)

(x) 99, 1.09, 1.27