est: Chapter 9 and 10 test (Copy) his Question: 3 pts This Test: 30 pts The mean
ID: 2947702 • Letter: E
Question
est: Chapter 9 and 10 test (Copy) his Question: 3 pts This Test: 30 pts The mean waiting time at the drive-through of a fast-food restaurant from the time an order is piaced to the time the order is received is 87 3 seconds A manager devises a 1066 new drive-through system that she believes will decrease wait time. As a test, she initiates the new system at her restaurant and measures the wat tme for 10 randomly selected orders. The wait times are provided in the table to the right Complete parts (a) and (b) below 953 688 57 8 75 7 673 70 6 79.0 EB Click the icon to view the table of (a) Because the sample size is small, the manager must verity that the wait time is normaly distibuted and the sample does not contain any outlers The normal probablity plot is shown below and the satisted The normal probability plot 6 9Explanation / Answer
samples are 106.6,68.8,57.8,75.7,67.3,81.2,95.3,87.7,70.6,79
correlation coeff=0.983
at 95% confidence and df=n-2=10-2=8
Critical value for r = 0.549.
If r is not between the positive and negative critical values, then the correlation coefficient is significant.
If r is significant, then you may want to use the line for prediction.
Here r (0.983) is not between -0.548 to +0.549 So r is significant
If the scatter plot looks linear then, yes, the line can be used for prediction, because r > the positive critical value.
Yes, the conditions are satisfied. The normal probability plot is linear? enough, since the correlation coefficient is greater than the critical value.
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