Business Statistics

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QMT2033 BUSINESS STATISTICS

Assignment for mid -term break

1. Most of the information technology developers claim that wireless connection would give speed of at least 11 Mbps compared to wired connection. A sample of 105 computers using wireless connection shows it gives a mean of 11.7 Mbps and a standard deviation of 2.3 Mbps. a) Do you think that the wireless usage should be implemented? Test at 7% significance level). b) Repeat the test by using p-value approach. 2. A jack is usually used for raising the axle of a motor so that a wheel may be changed. It is known that the weight of the vehicle that be raised by a jack is more than 100kg. a random sample of 125 jacks with a mean of 102.2kg and standard deviation of 15.17kg is taken. a) Do you agree that a jack can raise more than a 100 kg vehicle? (use α = 0.03) b) Repeat the test by using p-value approach. 3. In a normal situation, on average, a song needs a duration of at most 3.5 minutes to be played. The duration of a random sample of 11 songs is taken, and the data are as follows: 5.32 6.53 4.52 3.20 3.39 4.00 4.10 3.15 3.47 4.01 2.33 a) By using the data, do you agree with the statement that a song needs a duration of at most 3.5 minutes to be played? (use α = 0.05) b) Repeat the test by using p-value approach. 4. A researcher needs on average, 1.2 years to complete his short-term research. A random sample of 12 researcher are taken, and the duration (in years) to complete their research are recorded as below: 4.3 1.0 1.5 1.6 1.2 0.8 2.1 2.4 0.7 1.3 0.4

a) Do these data support the stamen that a researcher needs exactly 1.2 years to complete his research? (use α=0.05) b) Repeat the test by using p-value approach. 5. Newly purchased automobile tyres of a certain type are supposed to be filled with a pressure of at most 34 psi. A random sample of 36 such tyres was selected and it gives a sample mean of 34.66 psi and a standard deviation of 2.14 psi. a) Does this sample prove that such tyres fill...
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