PSYC1111 Study Guide - Final Guide: Null Hypothesis, Sample Size Determination, Statistical Hypothesis Testing
Hypothesis Testing
• The method in which we select samples to learn more about characteristics of a
given population is called hypothesis testing
Estiatig μ: Cofidee Iterval
• An interval estimate gives us a range of believable values
• This interval range is called confidence interval
o Boundaries within which we believe the true value of the mean will fall
Example: Determining a Liar or not
• Eka ad O’“ulliva 1991 reported for U“A seret servie agets:
o Sample mean M = 64.12
o Estimate of population standard deviation σ = 14.80
o Sample size: N=34
o Standard error of means:
The width of confidence intervals is affected by:
o Variation in the population of interest
o Greater variation in the population leads to a wider confidence interval
o Sample size
o Smaller sample size leads to a wider confidence interval
Small variation within the population of interest
• Samples more similar to each other
• The population estimate based on the sample more accurate
• Small width of the confidence interval
Large variation within the population of interest
• Samples are more different from each other
• We are less sure that the sample mean is close to the population mean
• Large width of the confidence interval
Small Samples
• vary more from each other
• more sampling error
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• smaller confidence about the estimation
• the width of the CL interval is larger
Large samples
• smaller variation between the samples
• the samples are more similar to each other
• the effect of sampling error is reduced
• larger confident about the estimation
• the width o the CL interval is smaller
Hypothesis Testing
• a method for testing a claim or a hypothesis about a parameter in a population,
using data measured in a sample
Step 1: State the hypothesis
The null hypothesis H0
• null or conservative state of affairs; no change, no difference, no relationship
• Example: comparing the instances of lung cancer between smokers and non-
smokers:
The alternatives hypothesis H1
• Complement of the null hypothesis: not tested directly but adopted upon a rejection
of the null hypothesis; change, difference, relationship
• It usuall epresses the eperieter’s elief aout the paraeter eig studies i.e.
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Document Summary
Hypothesis testing: the method in which we select samples to learn more about characteristics of a given population is called hypothesis testing. Esti(cid:373)ati(cid:374)g : co(cid:374)fide(cid:374)(cid:272)e i(cid:374)terval: an interval estimate gives us a range of believable values, this interval range is called confidence interval, boundaries within which we believe the true value of the mean will fall. Example: determining a liar or not: ek(cid:373)a(cid:374) a(cid:374)d o" ulliva(cid:374) (cid:894)1991(cid:895) reported for u a se(cid:272)ret servi(cid:272)e age(cid:374)ts, sample mean m = 64. 12, estimate of population standard deviation = 14. 80, sample size: n=34, standard error of means: The width of confidence intervals is affected by: variation in the population of interest, greater variation in the population leads to a wider confidence interval, sample size, smaller sample size leads to a wider confidence interval. Small variation within the population of interest: samples more similar to each other, the population estimate based on the sample more accurate, small width of the confidence interval.
