Daily Practice · Higher
October 2015 5-a-day
Printing for a group?
The batch download puts all 2 tiers' October 2015 sheets in a single PDF, each tier behind its own divider page - 62 sheets in one file.
Every sheet in October 2015
The same date always regenerates the same five questions, so a sheet you print today is the sheet a classmate prints tomorrow.
- 1st October 2015P(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).
- 2nd October 2015A histogram has unequal class widths. Explain why the height of a bar can no longer be read directly as the frequency.
- 3rd October 2015Box plot A has a median of 50 and box plot B has a median of 42, for the same type of data. What does this tell you about the two data sets?
- 4th October 2015A data set of ages is: 12, 13, 12, 14, -12, 13. Which value is clearly an error, and why?
- 5th October 2015A normal distribution has mean 100 and standard deviation 15. What range contains approximately 95% of the data?
- 6th October 2015A PMCC value of r = -0.2 is calculated. Describe the correlation.
- 7th October 2015A class interval 10-30 (width 20) has frequency density 3. Find the frequency.
- 8th October 2015A cumulative frequency graph for 100 test scores gives Q1 = 40, median = 58, Q3 = 70, minimum = 5, maximum = 98. Determine which of the minimum and maximum should be plotted as individual outliers.
- 9th October 2015P(A) = 0.6, P(A or B) = 0.75, and P(A and B) = 0.2. Find P(B).
- 10th October 2015The table shows weights, in kg, of 20 parcels: 0-5 (freq 4), 5-10 (freq 10), 10-15 (freq 6). Estimate the mean weight.
- 11th October 2015Rewrite the response options '0-5, 5-10, 10-15' so that they no longer overlap.
- 12th October 2015A series of 4-point moving averages is 45, 48, 52, 55. Describe the trend shown by these values.
- 13th October 2015A bag has only red, blue and green counters. P(red) = 0.5 and P(blue) = 0.2. Find P(green).
- 14th October 2015State one reason why a histogram has no gaps between its bars, unlike a bar chart.
- 15th October 2015Box plot A has an interquartile range of 8 and box plot B has an interquartile range of 15. What does this tell you about the spread of the middle 50 percent of each data set?
- 16th October 2015Using the boundaries from the previous question (2 and 50), state whether a value of 55 in the data set would be classed as an outlier.
- 17th October 2015Test scores are normally distributed with mean 65 and standard deviation 8. Estimate the percentage of students scoring between 65 and 81.
- 18th October 2015For a data set, Sxy = 30, Sxx = 50, Syy = 40. Calculate the PMCC to 3 significant figures.
- 19th October 2015A class interval has width 5 and frequency 20. Find the frequency density.
- 20th October 2015A data set has Q1 = 20 and Q3 = 32. Is a value of 55 an outlier? Use the 1.5 x IQR rule.
- 21st October 2015P(A) = 1/2, P(B) = 1/3, P(A and B) = 1/6. Find P(A or B).
- 22nd October 2015The table shows ages, in years, of 50 people at a gym: 10-20 (freq 6), 20-30 (freq 18), 30-40 (freq 16), 40-50 (freq 10). Estimate the mean age.
- 23rd October 2015What is wrong with the question 'How old are you and do you smoke?'
- 24th October 2015Find the 3-point moving average of 10, 14, 18.
- 25th October 2015P(A) = 0.4 and P(B) = 0.35, where A and B are mutually exclusive. Find P(A or B).
- 26th October 2015A histogram has bars of equal width. True or false: the height of each bar represents the frequency for that class.
- 27th October 2015Name the five values needed to draw a box plot.
- 28th October 2015A 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.
- 29th October 2015A normally distributed data set has mean 40 and standard deviation 3. Estimate the percentage of values above 43.
- 30th October 2015A 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.
- 31st October 2015A 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.