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Aliun [14]
3 years ago
5

A teacher administers a standardized math test to his class of 75 students. The mean score (out of 300 possible points) is 235.

From previous studies, you know the population standard deviation is 28. Using the sample data given, calculate a 95% confidence interval for the population mean.
Mathematics
1 answer:
Ede4ka [16]3 years ago
8 0

Answer:

(228.663 ; 241.337)

Step-by-step explanation:

Given that:

Mean (m) = 235

Standard deviation (s) = 28

α = 95%

Zcritical at 95% = 1.96

Sample size (n) = 75

The confidence interval of the population mean can be obtained using the relation :

Mean ± Error

Error = Zcritical * (s/sqrt(n))

Error = 1.96 * (28/sqrt(75))

Error = 1.96 * 3.2331615

Error = 6.33699654

Error = 6.337

Lower boundary = 235 - 6.337 = 228.663

Upper boundary = 235 + 6.337 = 241.337

(228.663 ; 241.337)

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Answer:

Total Dolls would Evelyn have had if she had not lost them = 9 Dolls

Step-by-step explanation:

As given,

Total dolls Evelyn had = 9

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So, Now

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If she had not lost te dolls , then she had 3 dolls more

∴ we get

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So, The answer would be :

Total Dolls would Evelyn have had if she had not lost them = 9 Dolls

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Answer:

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