Daily Practice · Higher
September 2012 5-a-day
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The batch download puts all 2 tiers' September 2012 sheets in a single PDF, each tier behind its own divider page - 60 sheets in one file.
Every sheet in September 2012
The same date always regenerates the same five questions, so a sheet you print today is the sheet a classmate prints tomorrow.
- 1st September 2012A data set of 10 house prices, in thousands of pounds, has a mean of 210 without an outlier of 900 included, but a mean of 279 when the 900 is included. Explain why a statistician might exclude the 900 when reporting a typical house price.
- 2nd September 2012A normally distributed data set has mean 40 and standard deviation 3. Estimate the percentage of values above 43.
- 3rd September 2012A regression line y = 12 + 1.5x is used to predict y when x = 200, even though the original x-values ranged only from 5 to 20. Explain why this prediction may be unreliable.
- 4th September 2012A histogram has classes 20-25 (frequency density 4), 25-35 (frequency density 2.4), 35-50 (frequency density 1.6). Find the total number of data values represented.
- 5th September 2012A data set has Q1 = 12 and Q3 = 20. Calculate the IQR and the upper outlier boundary.
- 6th September 2012Out of 50 people surveyed, 20 like tea, 25 like coffee, and 10 like both. Find the probability that a randomly chosen person likes tea or coffee.
- 7th September 2012A class interval 0-10 has frequency 6. Find frequency x midpoint.
- 8th September 2012A survey question offers the response options 'Never, Sometimes, Always'. State one improvement that could be made.
- 9th September 2012Find the 4-point moving average of 12, 16, 20, 10.
- 10th September 2012Are 'rolling an even number' and 'rolling a 5' on a normal six-sided dice mutually exclusive?
- 11th September 2012A histogram for exam scores has bars of equal width 10 marks, covering 0-10, 10-20, 20-30, 30-40, with heights 2, 8, 15, 5. How many students took the exam?
- 12th September 2012A box plot shows minimum 4 and maximum 36, with median 20. State the range of the data.
- 13th September 2012A data set has lower quartile Q1 = 20 and upper quartile Q3 = 32. Using the rule 'outlier if more than 1.5 x IQR beyond Q1 or Q3', find the outlier boundaries.
- 14th September 2012A normal distribution has mean 50 and standard deviation 5. What range of values contains approximately 68% of the data?
- 15th September 2012For a data set, Sxy = 45 and Sxx = 60. Find the gradient b of the regression line.
- 16th September 2012A histogram bar has height (frequency density) 2.5 and covers the interval 0-8. Find the frequency it represents.
- 17th September 2012A cumulative frequency table gives Q1 = 18, median = 25, Q3 = 34 for the ages of 60 people at a conference. Calculate the IQR and state the upper outlier boundary.
- 18th September 2012In a group of 40 students, 22 play football, 18 play rugby, and P(football or rugby) = 0.85. Find the number of students who play both sports.
- 19th September 2012Find the midpoint of the class interval 10-20.
- 20th September 2012What is wrong with the question 'Do you not think school lunches are too expensive?'
- 21st September 2012What does a moving average smooth out in seasonal data, and what does the result reveal?
- 22nd September 2012A card is drawn at random from a normal 52-card pack. Find P(drawing a King or a Queen).
- 23rd September 2012A histogram of ages has 5 equal-width bars covering 0-10, 10-20, 20-30, 30-40, 40-50 with heights 3, 7, x, 9, 2, and a total of 35 people. Find x.
- 24th September 2012A box plot has lower quartile 10 and upper quartile 22. Find the interquartile range.
- 25th September 2012Test scores out of 50 are: 32, 28, 35, 30, 29, 31, 95. Which score cannot be correct, and why?
- 26th September 2012The masses of 500 apples are normally distributed with mean 120 g and standard deviation 10 g. Estimate the number of apples with a mass between 110 g and 130 g.
- 27th September 2012The equation of a regression line is y = 3 + 2x. Find y when x = 5.
- 28th September 2012A frequency table has intervals 0-10 (frequency 15) and 10-15 (frequency 20). Calculate the frequency density for each.
- 29th September 2012Using the data in the previous question, a delegate aged 65 attends. Is this delegate's age an outlier? Explain.
- 30th September 2012P(A) = 0.4, P(B) = 0.3, P(A and B) = 0.1. Find P(A or B).