BMGT230 Business Statistics Final Exam Review Inference about the Population Mean Estimating the Population Mean The HP company operates service centers in various locations in the US and abroad where customers can call to get call 16 answers to questions about HP products Previous studies indicate that the distribution of time required for each is normally distributed with a mean equal to 540 seconds Company officials have selected a random sample of calls and wish to determine whether the mean call time has decreased after a training program was given to call 1 The appropriate hypotheses to test are center employees A Ho 540 vs Ha 540 B Ho 540 vs Ha 540 C Ho 540 vs Ha 560 D Ho 540 vs Ha 540 E none of the above Estimating the Population Mean The HP company operates service centers in various locations in the US and abroad where customers can call to answers to questions about HP products Previous studies indicate that the distribution of time required for each is normally distributed with a mean equal to 540 seconds Company officials have selected a random sample of 16 calls and wish to determine whether the mean call time has decreased after a training program was given to call 2 In the random sample of 16 calls the officials found that the sample mean was 510 seconds and the sample standard deviation was 45 seconds If they use a 1 level of significance then get call center employees A pvalue 0 01 B pvalue 0 0038 C pvalue 0 05 D pvalue 0 025 E 0 005 pvalue 0 01 Estimating the Population Mean The HP company operates service centers in various locations in the US and abroad where customers can call to get answers to questions about HP products Previous studies indicate that the distribution of time required for each call is normally distributed with a mean equal to 540 seconds Company officials have selected a random sample of 16 calls and wish to determine whether the mean call time has decreased after a training program was given to call In the random sample of 16 calls the officials found that the sample mean was 510 seconds and the sample standard deviation was 45 seconds If they use a 1 level of significance what decision should they make A The official cannot make a decision based on the information given center employees B Reject Ho C Accept Ho D Fail to reject Ho E None of the above Two Sample T Procedures 2 Sample T Tests A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies Group members took a random sample of 16 toothbrushes from Company A and 11 from Company B Each was charged overnight and the number of minutes of use before needing to be recharged was recorded Company A toothbrushes operated for an average of 119 minutes with a standard deviation of 1 7 minutes Company B toothbrushes operated for an average of 120 minutes with a standard deviation of 1 5 minutes Assuming that the operating times of cordless toothbrushes manufactured by the two companies are normally distributed with equal variances do the data indicate that Company B toothbrushes operate more minutes on average than Company A The correct null and alternative hypotheses assuming 1 stands for company A and 2 for company B are toothbrushes A H0 1 2 0 and HA 1 2 0 B H0 1 2 0 and HA 1 2 0 C H0 1 2 0 and HA 1 2 0 D H0 1 2 0 and HA 1 2 0 E None of the above 2 Sample T Tests A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by different companies Group members took a random sample of 16 toothbrushes from Company A and 11 from Company B Each was charged overnight and the number of minutes of use before needing to be recharged was recorded Company A toothbrushes operated for an average of 119 minutes with a standard deviation of 1 7 Company B toothbrushes operated for an average of 120 minutes with a standard deviation of 1 5 minutes that the operating times of cordless toothbrushes manufactured by the two companies are normally distributed equal variances do the data indicate that Company B toothbrushes operate more minutes on average than two minutes Assuming with Company A Toothbrushes The value of the test statistics is closest to A 1 57 B 1 61 C 0 149 D 0 149 E 1 57 2 Sample T Tests A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies Group members took a random sample of 16 toothbrushes from Company A and 11 from Company B Each was charged overnight and the number of minutes of use before needing to be recharged was recorded Company A toothbrushes operated for an average of 119 minutes with a standard deviation of 1 7 minutes Company B toothbrushes operated for an average of 120 minutes with a standard deviation of 1 5 minutes Assuming that the operating times of cordless toothbrushes manufactured by the two companies are normally distributed with equal variances do the data indicate that Company B toothbrushes operate more minutes on average than Company The rejection region for this test at 5 level of significance is A Toothbrushes A Reject Ho if test statistics 2 060 B Reject Ho if test statistics 1 708 C Reject Ho if test statistics 1 708 D Reject Ho if test statistics 2 060 E Reject Ho if test statistics 1 812 2 Sample T Tests A consumer group was interested in comparing the operating time of cordless toothbrushes manufactured by two different companies Group members took a random sample of 16 toothbrushes from Company A and 11 from Company B Each was charged overnight and the number of minutes of use before needing to be recharged was recorded Company A toothbrushes operated for an average of 119 minutes with a standard deviation of 1 7 minutes Company B toothbrushes operated for an average of 120 minutes with a standard deviation of 1 5 minutes Assuming that the operating times of cordless toothbrushes manufactured by the two companies are normally distributed with equal variances do the data indicate that Company B toothbrushes operate more minutes on average than Company A Toothbrushes At 0 05 I we reject the null hypothesis II we fail to reject the null hypothesis toothbrushes A I and III B I only C II only D III only E II and III III we can conclude that Company B toothbrushes operate more minutes on average than Company A 2 Sample T Tests Which of the following statements is true A This is a two tail test B This is paired design and a one tail test C This is paired design and a two tail
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