XR13-57 A diet doctor claims that the average Australian is more than 10 kg overweight. To test his.

XR13-57 A diet doctor claims that the
average Australian is more than 10 kg overweight. To test his claim, a random
sample of 100 Australians were weighed, and the difference between their actual
weight and their ideal weight was calculated and recorded. Some of the data are
listed below.

Do these data allow us to infer at the 5%
significance level that the doctor’s claim is true?

Q789;

XR13-58 A pizza outlet advertises that its
average waiting time is less than 12 minutes from the time an order is
placed. A random sample of waiting times (in minutes) for 50 orders was
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XR13-57 A diet doctor claims that the
average Australian is more than 10 kg overweight. To test his claim, a random
sample of 100 Australians were weighed, and the difference between their actual
weight and their ideal weight was calculated and recorded. Some of the data are
listed below.

Do these data allow us to infer at the 5%
significance level that the doctor’s claim is true?

Q789;

XR13-58 A pizza outlet advertises that its
average waiting time is less than 12 minutes from the time an order is
placed. A random sample of waiting times (in minutes) for 50 orders was
recorded. A portion of this sample is shown below.

10.4           10.8            
10.0           13.2 …   14.8         8.8        8.2

a Is this sufficient evidence to support
the pizza outlet’s advertisement, at the 5% level of significance?

b What assumption must be made in order to
answer part (a)? Use whatever graphical technique you deem appropriate to
confirm that the required condition is satisfied.

Q790;

XR13-59 Companies that sell groceries over
the internet are called e-grocers. Customers enter their orders, pay by credit
card, and receive delivery by truck. A potential e-grocer analysed the market
and determined that to be profitable the average order would have to exceed
$85. To determine whether an e-grocery would be profitable in one large city,
she offered the service and recorded the size of the order for a random sample
of customers. Can we infer from these data that an e-grocery will be profitable
in this city?

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