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The standard error of the sample proportion under H0?

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Important Questions on Tests of Significance – Basic Concepts and Large Sample Tests

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The label on a jar of jam carries the words 'minimum contents 272 g'.

The mass of jam dispensed by a machine used to fill the jars is a normally distributed random variable with mean 276 g. The variance of the mass of the jam, in grams2, dispensed by the machine is 1.82. Each week there is a check to see if the mean mass dispensed by the machine is 276 g. One particular week a sample of eight jars is checked. The mean mass of jam in these jars is 277.7 g. Carry out an appropriate hypothesis test at the 5% level of significance, stating any assumptions you have made.

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What is the standard error of the difference between two sample proportions, (Px-Py)

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Find standard error of the sample proportion P=0.45 when the population proportion is 0.5 and the given sample size is 100

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The manufacturer of a certain smartphone advertises that the average charging time for the battery is 80 minutes with standard deviation 2.6 minutes. Owners of these smartphones suggest that the time is longer. A random sample of the phones were charged from 0 to 100% and their times, in minutes, are as follows.

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Investigate at the 5% level of significance whether or not the manufacturer's claim is justified, stating any assumption(s) you have made.

HARD

Calculate standard error of the sample means, when sample mean is 100, sample size is 64 and population standard deviation is 24.

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The given length of time a charged smartphone battery will last is normally distributed with mean 24 hours. The variance of the time taken, in minutes, for the smartphone to work is 1. The variance of the length of time time taken, in hours squared, for the battery to last is 1. Sami tests a random sample of five batteries;

the sample mean time is 23.2 hours. Investigate at the 5% level of significance whether the time batteries last is less than the time given, stating any assumption(s) you make.

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Calculate standard error of the sample means, when sample mean is 100, sample size is 25 and population standard deviation is 50.

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What is the standard error of the sample proportion under H0?

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Find standard error of the sample mean given that the variance of a given sample of size 150 is 144
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If a random sample of 10 observations has variance 625 then standard error is
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Calculate standard error of the sample mean, when sample mean is 100, sample size is 64 and population standard deviation is 24

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The label on a jar of jam carries the words 'minimum contents 272 g'.

Explain why, in practice, the average contents need to be greater than 272 g.

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If a random sample of 10 observations has variance 324 then standard error is
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What is the standard error of the difference between two sample proportions, (Px-Py)

MEDIUM

If m=35,n=40,x=10.8,y=11.9, SX=3 and SY=4, then calculate standard error of X--Y-

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What is the standard error of the difference between two sample proportions, (Px-Py)