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A students received a score of 50 on his history test. The test had a mean of 69 and a standard deviation of 10. Find the z score and assess whether his score is considered unusual.

1.90; unusual

–1.90; not unusual

–1.90; unusual

1.90; not unusual

Respuesta :

Answer:

c) The Z-score = - 1.90 unusual

Step-by-step explanation:

Explanation:-

Let 'X' be the random variable in normal distribution

Given student received a score X = 50

Mean of the Population x⁻ = 69

standard deviation of the Population 'σ' = 10

now

[tex]Z = \frac{x^{-}-mean }{S.D}[/tex]

[tex]Z = \frac{x^{-}-mean }{S.D} = \frac{50 -69}{10} = - 1.90[/tex]

The Z-score = - 1.90

Conclusion:-

The Z-score = - 1.90 unusual