Two cosmetics manufacturers produce similar hairspray products. Manufacturer 1 asserts that its hairspray holds longer, on average, than does its competitor’s product. To test the claim, we randomly sample 20 hairspray users and have half of them use brand 1 hairspray while the other half use brand 2. The average hold time for brand 1 is 18.5 hr with a standard deviation of 6.28 hr. The average hold time for brand 2 is 17.95 hr with a standard deviation of 8.55 hr. Does the sample support manufacturer 1’s assertion? Assume that the populations in question are both normal and have unequal variances. Select the appropriate critical value (CV), test statistic (TS), decision and conclusion. (Useα= 0.10).
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CV = 1.3368; TS = 0.16; rejectH0; Conclusion: There exists a statistically significant difference in hold.
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CV = 1.3304; TS = –0.23; fail to rejectH0; Conclusion: There is no statistically significant difference in hold.
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CV = –2.5835; TS = 0.23; rejectH0; Conclusion: There exists a statistically significant difference in hold.
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CV = 1.3368; TS = 0.16; fail to rejectH0; Conclusion: There is no statistically significant difference in hold.
Amborella trichopoda flower, similar to a hypothesized early flower
Similar traits may not be homologous
Four different spindle attachments produce four second-division segregation patterns
(a) Homologous traits are similar due to shared ancestry. (b) Analogous traits (bats’, birds’, and f
Selected Natural Products
GeneChip (Affymetrix, Inc.) after hybridization to p53 PCR products