Reflection across y=x​

What signals you that factoring by grouping is the best method to use when factoring a problem?

Two blends of tea are mixed to make a blend that will be sold at the fair. black tea sells for $2.20 per pound and orange pekoe tea sells for $3.00 per pound. how much of each should be used to obtain a 4lb blend selling for $2.50 per pound?

Do social recommendations increase ad effectiveness? a study of online video viewers compared viewers who arrived at an advertising video for a particular brand by following a social media recommendation link to viewers who arrived at the same video by web browsing. data were collected on whether the viewer could correctly recall the brand being advertised after seeing the video. the results are given below. correctly recalled the brandarrival 409153browsing20484b. conduct the hypothesis test, using the 0.025 level of significance. what is the value of the test statistic? χ2stat=what is the p-value? p-value=is this value significant atα=0.025?