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Qplstion 10 1 points Save Answer It s known that the mean age of the populaiton of doctors in some community is 51 years. What Is the expected value of the sampling distribution of the samp'e mean? Round your answer to the whole number of years. Question 1 1 1 points Save Answer The standard deviation ofan innite population is 20.69. Forthe sample size of 45, nd the standard deviation of the sampling distribution of the sample mean. Round your answer to two decimal places. Question 12 2 points Save Answer A sample of 42 bank accounts was taken to verily ifa recent news release affected howI much customers held in their accounts. The sample mean appeared to be 13,769.97. and it is known that the population standard deviation ottunds in bank accounts is 489.45. What is the left boundary of 97% confidence interval? Use Excel for all computations and round your nal answer to 2 decimals. Question 7 1 points Save Answer To estmate the mean number of days a stock has pOSItive daily increases within a year. business researchers initiated a study. From preVious similar studies it is known that the standard deviation of the population is 6.43. With this planning value. what sample size must now be taken for the 95% condence interval to have the margin of error of 1.09? Use the fact that 95% of normally distributed observations are Within 1.96 standard deviaitdns. Gve your answer with 2 decimals. Do NOT round the sampe size to a whole number. For example. if you obtain 456.76 for the sample size. enter this value. not 457. Question 8 1 points Save Answer It is known that for a = 0.1. Zajz = 1.645. Using this fact. solve the following problem. A sample of 75 comahies was taken to find out how many companies went bankrupt over the period of 10 years. The proportion ofthe companies which led bankruptsy appeared to be 0.28 in the sample. What is the left boundary of 90% condence interval to estimate the proportion of bankrupt companies overthe period of 10 years? Assume that the conditions for the samling distribution to be approximately normal are satised. Round your answer to 4 decimals. Question 9 2 points Save Answer If the population stadard deviaiton is equal to 5.14 and the sample size is 94, what is the margin of error for the corresponding 979% confidence interval to estimate the population mean? Use Excel to calculate and round your answer to 2 decimals