Question 3 : I got one section, but on the pic I marked red ?, how do I get that part, b/c once I get that part, then I'll get the answer, and once I get the answer I need to sqrt to what the answer gives me, then I'll have my complete answer. Is only that part I do nott know and i need help on it

Question 4 : I have a really hard time understanding, and I'm not sure if I need to use R studio or naw. & struggle with this type of questions a lot it confuses me ???

3) A sample of 31 boxes of cereal has a sample standard deviation of 0.81 ounces. Construct a 95% confidence interval to estimate the true standard deviation of the filling process for the boxes of cereal. n = 31 =# 31 - 1 = 30 R - STUDIO 5 =.81 A) (0.525, 1.095) * 1 -. 95 : 0.05 > ( 31 - 1 ) * ( . 81 ) 1 2 1 9chis9 ( 0.975 , 30 ) B) (0.419, 1.172) 0.05 : 2 = 0.025 > 0. 4 189 723 C) (0.647, 1.083) 0.025 + . 95 = 0.975 D) (0.719, 0.719) E) None of the above. > (31 - 1) # (81 ) " 2 / qchisq ( 30 ) VO . 418 9 723 S 0. 6472 4) The random variable X has cumulative distribution function: F(x ) - 12x - x 2 The random variable Y=12X+8 when X20 and Y=0 if X is negative. Find E[Y]. A) 10 B ) O C) 32 D) 8 E) 40 F) None of the above