Kaelyn has 14 coins that have a value if $1.20. she only had dimes and nickles. How many nickels does kaelyn have?
2 answers:
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Answer:
We are confident at 99% that the difference between the two proportions is between
Step-by-step explanation:
Part a
Data given and notation
represent the number people registered as Democrats
represent the number of people registered as Republicans
sampleselcted
represent the proportion of people registered as Democrats
represent the proportion of people registered as Republicans
The standard error is given by this formula:
And the standard error estimated given by the problem is 0.008
Part b
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
represent the real population proportion of Democrats that approve of the way the California Legislature is handling its job
represent the estimated proportion of Democrats that approve of the way the California Legislature is handling its job
is the sample size for Democrats
represent the real population proportion of Republicans that approve of the way the California Legislature is handling its job
represent the estimated proportion of Republicans that approve of the way the California Legislature is handling its job
is the sample for Republicans
represent the critical value for the margin of error
The population proportion have the following distribution
The confidence interval for the difference of two proportions would be given by this formula
For the 90% confidence interval the value of and
, with that value we can find the quantile required for the interval in the normal standard distribution.
And replacing into the confidence interval formula we got:
And the 99% confidence interval would be given (0.380;0.420).
We are confident at 99% that the difference between the two proportions is between