Find a 90% confidence interval for the population mean if the sample mean is 1250 with a standard deviation of 35 for sample of 20. Note sample size is less than 30 and population standard deviation is unknown. Be sure to use a t score

Find the minimum sample size to find a 90% interval estimate for a population proportion if a previous sample had a sample proportion of 45% and you want to be accurate within 4% of the true proportion.

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