Bivariate Data Exam

What kind of data is the country of residence of overseas students?

• quantitative: continuous

• quantitative: discrete

• categorical: ordinal

• categorical: nominal

• None of the above

Which of the following would provide a unbiased sample?

• Using your calculator to find random numbers to select a sample of 120 students

• Asking every student in your class

• Use random numbers to choose six students in your class

• Ask anyone to text their answers to your mobile phone

• Ask the first 50 people leaving your local supermarket

Which of the following would be a clear and unbiased question?

• What sort of car do you drive?

• Considering water wastage, how long do you usually spend in the shower?

• Is green your favourite colour?

• Do you drive a high powered car?

• Do you think our hopeless government is corrupt? (Yes/No)

Find the mean, median and mode of the following numbers.

1 . 2 . 1 . 2 . 0 . 12 . 12 . 1 . 6 . 9

• 4.6, 6 and 1

• 6, 1 and 4.6

• 2, 4.6 and 1

• 4.6, 2 and 1

• 1, 6 and 4.6

Calculate the coefficient of determination for the data in the table below.

• 23%

• 25%

• 28%

• 32%

• 36%

A student adds up the time, in hours, spent studying for each topic and the test scores for each topic, as a percentage. She finds the correlation coefficient to be 0.87. To the nearest whole percentage, what percentage of the variation in her test scores can be explained by the variation in time spent studying?

• 70%

• 72%

• 76%

• 80%

• 83%

Two random variables have been observed and calculated to be connected by the equation y = 44.92 + 0.11x. The coefficient of determination is 0.42. Find the value of Pearson’s product-moment correlation coefficient, correct to two decimal places.

• 0.65

• –0.65

• ±0.65

• 0.72

• ±0.72

The regression line modelling the amount of chemical (kg) produced by a reactor is measured against the temperature (ºC) of the reactants. The regression line modelling the results has the equation:

Amount of chemical produced = 15.50 + 1.17 × temperature

Use the model to predict, to the nearest kilogram, the quantity of chemical produced at 60ºC.

• 34 kg

• 64 kg

• 86 kg

• 133 kg

• 180 kg

The regression line modelling the amount of chemical (kg) produced by a reactor is measured against the temperature (ºC) of the reactants. The regression line modelling the results has the equation:

Amount of chemical produced = 83.76 – 0.79 × temperature

Use the model to predict to the nearest degree the temperature you would expect to produce 59 kg of chemical.

• 18ºC

• 31ºC

• 37ºC

• 42ºC

• 52ºC

Data is collected on people aged between 10 and 21. A line of best fit is used to predict results. Predicting results for which age would be an example of interpolation?

• 7 years old

• 18 years old

• 24 years old

• 26 years old

• 35 years old