Edexcel S3 2020 October — Question 4

Exam BoardEdexcel
ModuleS3 (Statistics 3)
Year2020
SessionOctober
TopicChi-squared distribution

4. Luka wants to carry out a survey of students at his school. He obtains a list of all 280 students.
  1. Explain how he can use this list to select a systematic sample of 40 students. Luka is trying to make his own random number table. He generates 400 digits to put in his table. Figure 1 shows the frequency of each digit in his table. \begin{table}[h]
    Digit generated0123456789
    Frequency36423341444348383243
    \captionsetup{labelformat=empty} \caption{Figure 1}
    \end{table} A test is carried out at the \(10 \%\) level of significance to see if the digits Luka generates follow a uniform distribution. For this test \(\sum \frac { ( \mathrm { O } - \mathrm { E } ) ^ { 2 } } { \mathrm { E } } = 5.9\)
  2. Determine the conclusion of this test.
    (3) The digits generated by Luka are taken two at a time to form two-digit numbers. Figure 2 shows the frequency of two-digit numbers in his table. \begin{table}[h]
    Two-digit numbers generated\(00 - 19\)\(20 - 39\)\(40 - 59\)\(60 - 79\)\(80 - 99\)
    Frequency3149304248
    \captionsetup{labelformat=empty} \caption{Figure 2}
    \end{table}
  3. Test, at the \(10 \%\) level of significance, whether the two-digit numbers generated by Luka follow a uniform distribution. You should state the hypotheses, the degrees of freedom and the critical value used for this test. There are 70 students in Year 12 at his school.
  4. State, giving a reason, the advice you would give to Luka regarding the use of his table of numbers for generating a simple random sample of 10 of the Year 12 students.