1. The average life expectancy of dishwashers produced by a company is 6 years with a standard deviation of 8 months. Assume that the lives of dishwashers are normally distributed. Which of the following statements are correct?The probability that a randomly selected dishwasher will have a life expectancy of at least 7 years is 0.0668.If 155 of this year's dishwasher production fail operating in less than 4 years and 4 months, the number of dishwashers produced this year was 30,000.The dishwashers that fail operating in less than 4.5 years will be replaced free of charge. The percent of dishwashers are expected to be replaced free of charge is 1.22%.The 95% confidence interval of the life expectancy of the dishwashers' lives is 56.32~87.68 in months.A department store has determined that 25% of all their sales are credit sales. A random sample of 60 sales is selected. Which of the following statements are correct?The standard error of the sampling distribution of p-hat is 0.056.The probability that the sample proportion will be greater than 0.30 is 0.1897.The expectation of the sampling distribution of p-hat is 0.25.The probability that the sample proportion will be between 0.20 to 0.30 is 0.7586.