Daily Practice · Foundation
July 2011 5-a-day
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The batch download puts all 2 tiers' July 2011 sheets in a single PDF, each tier behind its own divider page - 62 sheets in one file.
Every sheet in July 2011
The same date always regenerates the same five questions, so a sheet you print today is the sheet a classmate prints tomorrow.
- 1st July 2011A table has class intervals with frequency x midpoint totals of 45, 120, 90 and frequencies 5, 8, 6. Find the estimated mean.
- 2nd July 2011Explain why a pilot survey should be carried out before the full survey is sent out.
- 3rd July 2011Find the 4-point moving average of 12, 16, 20, 10.
- 4th July 2011P(rain) = 0.3 and P(snow) = 0.05 on a given day, and rain and snow are mutually exclusive that day. Find P(rain or snow).
- 5th July 2011Using the same histogram, how many students scored between 10 and 30 marks?
- 6th July 2011A box plot has lower quartile 10 and upper quartile 22. Find the interquartile range.
- 7th July 2011The heights (cm) of 6 plants are: 15, 18, 16, 14, 17, 150. Find the mean of the remaining values after removing the outlier.
- 8th July 2011Explain why a crude rate is more useful than a raw total, such as the total number of deaths, when comparing two towns of different sizes.
- 9th July 2011A factory has 400 workers: 160 in production, 120 in packing and 120 in admin. A stratified sample of 50 workers is needed. Find how many should be sampled from packing.
- 10th July 2011Using the same table (0:4, 1:10, 2:4, 3:2), find the mean number of siblings.
- 11th July 2011The mean rainfall in April was 45 mm with a range of 20 mm; in May it was 45 mm with a range of 8 mm. Compare April and May.
- 12th July 2011A cost index for electricity, relative to the same base year, was 120 in 2021 and 150 in 2023. Find the percentage increase in the cost of electricity from 2021 to 2023 (not from the base year).
- 13th July 2011The probability that a train is late is 0.15. Out of 200 trains, how many would you expect to be late?
- 14th July 2011The probability that a machine produces a faulty item is 0.04. Out of 300 items, how many would you expect to be faulty?
- 15th July 2011A box has 3 faulty bulbs out of 10. Two bulbs are chosen without replacement. Find the probability at least one is faulty.
- 16th July 2011In a pyramid, the bars for ages 65+ are unusually long compared with younger age bands. Give one possible reason.
- 17th July 2011A data set has mean 12, median 12, mode 12. Describe its skew.
- 18th July 2011A sample of 80 light bulbs from a batch of 2000 found 4 were faulty. Estimate the number of faulty bulbs in the whole batch.
- 19th July 2011The mean of 6 numbers is 15. Five of the numbers are 10, 12, 14, 18, 20. Find the sixth number.
- 20th July 2011State one advantage of random sampling.
- 21st July 2011What is meant by a control variable?
- 22nd July 2011Values of 12, 18, 25, 31, 9, 22, 15 are grouped using intervals 0 <= x < 10, 10 <= x < 20, 20 <= x < 30, 30 <= x < 40. State the frequency of the interval 10 <= x < 20.
- 23rd July 2011A pie chart shows four categories with angles 90, 120, 60 and x degrees. Find x.
- 24th July 2011Events A and B are mutually exclusive with P(A) = 0.3 and P(B) = 0.25. Find P(A or B).
- 25th July 2011Explain why estimating a y-value for x = 50 would be unreliable if all the plotted data only covers x-values from 0 to 20.
- 26th July 2011Two variables have a correlation coefficient close to 0. What does this suggest?
- 27th July 2011The Spearman's rank correlation coefficient between temperature and ice cream sales for 8 days is rs = 0.95. Describe the correlation.
- 28th July 2011A pilot survey shows that many respondents left a question blank. What might this suggest about the question?
- 29th July 2011A researcher records the exact temperature of 30 cups of tea to the nearest 0.1 degrees C. State the type of data, giving two features.
- 30th July 2011Group A has 4 items with mean 12. Group B has 4 items with mean 20. Find the combined mean.
- 31st July 2011The number of pets owned by 15 households, recorded as collected, is: 0,1,2,1,0,3,1,2,0,1,1,2,0,1,2. Complete a frequency table for the number of pets and state the total frequency.