Defective alternator and corroded or loose battery charges are a few of the main causes of battery degradation. A company producing automobile batteries is developing a prototype on their next product and that they claim their batteries will last on average, 3 years with a variance of 1 year. A random sample of 5 prototype batteries were taken and in the course of the company’s product development, have measured their lifetimes as 1.9, 2.4, 3.0, 3.5, and 4.2 years.

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CI on Variance
Defective alternator and corroded or loose battery charges are a few of the main causes of battery
degradation. A company producing automobile batteries is developing a prototype on their next product
and that they claim their batteries will last on average, 3 years with a variance of 1 year. A random sample
of 5 prototype batteries were taken and in the course of the company’s product development, have
measured their lifetimes as 1.9, 2.4, 3.0, 3.5, and 4.2 years.
Construct a 95% confidence interval for o and decide if the company's claim that o? = 1 is valid. Assume
the population of battery lives to be approximately normally distributed.
O a. 0.34 < o2 < 4.59. Because 95% confidence interval for o? is (0.34, 4.59), and the s2 = 0.815
is in that interval, we can conclude that the company's claim is valid
O b. 0.29 < o² < 6.74. 95% confidence interval for o² is (0.29, 6.74)
O c. 0.539 < o < 2.596. Because 95% confidence interval for o is (0.539, 2.596), and 1 is in that
interval, we can conclude that the company's claim that o = 1 is valid
O d. 0.29 < o? < 6.74. Because 95% confidence interval for o? is (0.29, 6.74), and 1 is in that
interval, we can conclude that the company's claim that o? = 1 is valid
%3D
Transcribed Image Text:CI on Variance Defective alternator and corroded or loose battery charges are a few of the main causes of battery degradation. A company producing automobile batteries is developing a prototype on their next product and that they claim their batteries will last on average, 3 years with a variance of 1 year. A random sample of 5 prototype batteries were taken and in the course of the company’s product development, have measured their lifetimes as 1.9, 2.4, 3.0, 3.5, and 4.2 years. Construct a 95% confidence interval for o and decide if the company's claim that o? = 1 is valid. Assume the population of battery lives to be approximately normally distributed. O a. 0.34 < o2 < 4.59. Because 95% confidence interval for o? is (0.34, 4.59), and the s2 = 0.815 is in that interval, we can conclude that the company's claim is valid O b. 0.29 < o² < 6.74. 95% confidence interval for o² is (0.29, 6.74) O c. 0.539 < o < 2.596. Because 95% confidence interval for o is (0.539, 2.596), and 1 is in that interval, we can conclude that the company's claim that o = 1 is valid O d. 0.29 < o? < 6.74. Because 95% confidence interval for o? is (0.29, 6.74), and 1 is in that interval, we can conclude that the company's claim that o? = 1 is valid %3D
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