score 0/16,66 points Previous Answers DevoreStat7 7.P.005. My Notes Ask Your Teacher Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation 0.75. (a) Compute a 90% CI for the true average porosity of a certain seam if the average porosity for 24 specimens from the seam was 4.85. (Give answers accurate to 2 decimal places.) Lower Limit 5.10 Upper Limit 4.60 (b) Compute a 99% CI for true average porosity of another seam based on 12 specimens with a sample average porosity of 4.56. (Give answers accurate to 2 decimal places.) Lower Limit 5.12 Upper Limit 4 (c) How large a sample size is necessary if the width of the 95% interval is to be 0.42? n 48.980 x Did you round up? (d) What sample size is necessary to estimate true average porosity to within 0.22 with 90% confidence? n = 37.823 Show transcribed image text score 0/16,66 points Previous Answers DevoreStat7 7.P.005. My Notes Ask Your Teacher Assume that the helium porosity (in percentage) of coal samples taken from any particular seam is normally distributed with true standard deviation 0.75. (a) Compute a 90% CI for the true average porosity of a certain seam if the average porosity for 24 specimens from the seam was 4.85. (Give answers accurate to 2 decimal places.) Lower Limit 5.10 Upper Limit 4.60 (b) Compute a 99% CI for true average porosity of another seam based on 12 specimens with a sample average porosity of 4.56. (Give answers accurate to 2 decimal places.) Lower Limit 5.12 Upper Limit 4 (c) How large a sample size is necessary if the width of the 95% interval is to be 0.42? n 48.980 x Did you round up? (d) What sample size is necessary to estimate true average porosity to within 0.22 with 90% confidence? n = 37.823

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Answer to score 0/16,66 points Previous Answers DevoreStat7 7.P.005. My Notes Ask Your Teacher Assume that the helium porosity (in…