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  • Perplex
    IB Math AIHL
    /
    Inference & Hypotheses
    /

    Problems

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    Problem Bank - Inference & Hypotheses

    Access custom-built, exam-style problems for inference & hypotheses. Each problem has a full solution and mark-scheme, as well as AI grading and support.

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    2 / 41 problems visible - Upgrade to view all problems

    IB: 4
    1

    !!

    0 / 8

    Dr. Z thinks his class performed better on a recent exam than Mr. X's class. The scores of students in each class are displayed in the following table:

    <ul>
<li>A two-row table with gridlines. The top has a merged header cell labeled “Score” spanning five columns.</li>
<li>Row labels at the left: “Dr. Z” and “Mr. X.”</li>
<li>Dr. Z row contains five scores under the header: 72, 67, 70, 67, 71.</li>
<li>Mr. X row contains seven scores: 64, 72, 61, 69, 55, 71, 66. The last two cells extend beyond the span of the “Score” header.</li>
</ul>

    Dr. Z decides to conduct a t-test at the 10% significance level.

    1. Write down the null and alternative hypotheses for this test.

      [1]
    2. Determine with justification the conclusion of this test.

      [5]
    3. State the two assumptions Dr. Z makes in using a t-test.

      [2]
    2

    !

    0 / 8

    A toy company advertises that the types of mini-figures found in its cereal packets occur in the following long-run proportions:

    Figure type

    Robot

    Wizard

    Athlete

    Alien

    Claimed proportion

    0.25

    0.30

    0.25

    0.20

    A random sample of 160 packets is opened, giving the observed frequencies:

    Figure type

    Robot

    Wizard

    Athlete

    Alien

    Total

    Observed frequency

    46

    42

    40

    32

    160

    1. State the null hypothesis H0​​ and the alternative hypothesis H1​​ for a χ2 goodness-of-fit test on the data.

      [2]
    2. Copy the table below and complete the expected-frequency row, correct to the nearest integer.

      Figure type

      Robot

      Wizard

      Athlete

      Alien

      Expected frequency





      [2]
    3. Determine

      1. the value of the χ2 test statistic.

        [1]
      2. the p-value of the test.

        [1]
    4. At the 5% significance level, state with a reason whether the company’s claim should be rejected.

      [2]

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