What is the critical value equal to?

A researcher wants to study the effect of bold and underlined words on students. A group of 20 students received a syllabus with the academic integrity section in bold and underlined words while another group of 20 students received the same copy except everything was in normal font. For the group with the bold and underlined words, the mean number of students who violated the academic integrity policy was 1.5 with a sample variance of 0.85. For the group with the normal font, the mean number of students who violated the academic integrity policy was 2.3 with a sample variance of 1.22. Does the result indicate a significantly higher mean number of students who violated the academic integrity policy if they got the normal font syllabus compared to the bold and underlined group? Use a 5% significance level. Note: Here, 1 indicates the group with normal font and 2 indicates the group with bold and underlined font. What is the critical value equal to? O 1.697 2.021 O 2.042 1.684