A sample of 400 items is taken from a normal population population whose mean as well as varience is 4.if the sample mean is 4.5, can the sample be regarded as a turly random sample?

Asked by Rupali Sharma | 29th May, 2014, 09:14: PM

Expert Answer:

S t e p space 1 : thin space H subscript o : U equals 4 comma space H subscript 1 : U not equal to 4 S t e p space 2 : thin space z equals fraction numerator 4.5 minus 4 over denominator begin display style fraction numerator S tan d a r d space D e v i a t i o n over denominator square root of n end fraction end style end fraction  G i v e n space comma space n space equals space 400 comma space V a r i a n c e space equals space 4 comma space S o space S tan d a r d space d e v i a t i o n space equals space square root of 4 equals 2  z equals space fraction numerator 0.5 cross times 20 over denominator 2 end fraction equals 5  S o space s a m p l e space i s space n o t space r e g a r d e d space a s space t r u l y space r a n d o m space s a m p l e.

Answered by Dharma Teja | 4th Jun, 2014, 02:54: PM

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