Use for Questions 1 and 2 A grocery store takes a random sample of 200 customers. The average check-out time is 4 minutes with a standard deviation of two minutes. 1. The standard error of the mean is? 2. The 95% confidence level for the true average check-out time is? 3. A random sample of 244 observations has a mean of 10, a median of 12 and a mode of 33. The population deviation is known to equal 2.8. the 95.44% confidence interval for the population mean is? 4. The following random sample was collected: 22 33 44 6 The 80% confidence interval for the mean is?
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