Cho hình vuông ABCD có cạnh bằng a. Gọi M, N là 2 điểm trên các cạnh AB, AD sao cho chu vi tam giác AMN = 2A . CM đường thẳng MN luôn tiếp xúc với 1 đường tròn cố định

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?