# Past Exam for STA 2023 - Statistical Methods with Murphy at Valencia Comm College (VCC)

## Exam Information

 Material Type: Mid-Term Professor: Murphy Class: STA 2023 - Statistical Methods Subject: STA: Statistics University: Valencia Community College Term: 1999 Keywords: Following EventsDistributionNormal CurveStandard DeviationsProbability.

## Sample Document Text

1 That old refrigerator. KEY 1) The lifetime of a refrigerator is a normal distribution with a mean of ten years and a standard deviation of 1.5 years. a) Sketch the distribution of X which represents the lifetime of this particular brand of refrigerator. X 5.5 7 8.5 10 11.5 13 14.5 Refrigerator Lifetime in Years b) What percentage of refrigerators last between 6.2 and 9.1 years? normalcdf(6.2, 9.1, 10, 1.5) = 0.2686038705 About 26.86%. c) What percentage of refrigerators last more that 12 years and 6 months? normalcdf(12.5, 1E99, 10, 1.5) = 0.0477903304 About 4.78%. d) What percentage of refrigerators last less than 5 years? normalcdf(-1E99, 5, 10, 1.5) = 4.291165336E-4 About 4.29E-4 = 0.000429 = 0.0429%. e) Would it be highly unlikely for a refrigerator to last less than five years? Justify your answer. It is highly unlikely that a refrigerator l...