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Hypothesis Testing. Population Proportion ( ). Notation. n = sample size. p = population proportion of hits or successes, used in the null hypothesis. q = 1 – p = population proportion of misses or failures. . p = x/n = sample proportion of hits.
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Hypothesis Testing Population Proportion ( )
Notation n = sample size p = population proportion of hits or successes, used in the null hypothesis. q = 1 – p = population proportion of misses or failures p = x/n= sample proportion of hits
Test Statistic for Testing a Claim about a Population Proportion, p p - p z = pq n
Find the P-value of the Z score. Reject the null hypothesis if the P-value is less than or equal to the significance level (Reject Ho if P-value < ) Fail to reject the null hypothesis if the P-value is greater than
p sometimes is given directly “10% of the observed sports cars are red” is expressed as p = 0.10 (determining the sample proportion of households with cable TV) p sometimes must be calculated “96 surveyed households have cable TV and 54 do not” is calculated using x 96 p = = = 0.64 n (96+54)
CAUTION • When the calculation of p results in a decimal with many places, store the number on your calculator and use all the decimals when evaluating the z test statistic. • Large errors can result from rounding p too much.
For math fans: Prove z = p - p pq n x np x - µ x - np n n p - p z = = = = pq npq npq n n