A physical instructor claims that the mean weight of students in school is greater than 82 kg with standard deviation 20. If a sample of size 81 students is selected with mean weight of 90. The test statistic equals to

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SSC CGL Tier-II ( JSO ) 2021 Official Paper ( Held On: 10 August 2022 )
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  1. z = 3.0
  2. z = 3.6
  3. z = 2.4
  4. z = 3.2

Answer (Detailed Solution Below)

Option 2 : z = 3.6
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SSC CGL Tier 1 2025 Full Test - 01
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Detailed Solution

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The correct answer is z = 3.6

Key Points

  • The test statistic is a measure of the difference between the sample mean and the population mean in terms of standard deviations.
  • In this case, the test statistic can be calculated as follows:
    • z = 3.6

 Additional Information

  • The test statistic is a measure of the difference between the sample mean and the population mean in terms of standard deviations.
  • The test statistic is calculated by dividing the difference between the sample mean and the population mean by the standard deviation divided by the square root of the sample size.
  • The test statistic can be used to determine the significance of the difference between the sample mean and the population mean.
  • If the test statistic is large enough, it can be concluded that the sample mean is significantly different from the population mean.

​ Important Points

  • The test statistic
    • It is only meaningful if the sample is a random sample.
    • It assumes that the population is normally distributed.
    • It is only one piece of information used to make inferences about the population mean.
      • Other factors, such as the sample size and the variability of the population, must also be taken into account.

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