Based on internal tests a spaghetti sauce company believes that 70% of people prefer their sauce to the competitor's sauce. they are going to conduct a taste test and want to have a probability of .9 or better that 60% or more of taste testers prefer their product. they are considering groups of taste testers in increments of 10, i. e., 10, 20, 30, 40, how many people do they need to participate in the taste test? note: your answer will be divisible by 10 with no remainder. use excel to you find the answer.

At the olympic games, many events have several rounds of competition. one of these events is the men's 100-meter backstroke. the upper dot plot shows the times (in seconds) of the top 8 finishers in the final round of the 2012 olympics. the lower dot plot shows the times of the same 8 swimmers, but in the semifinal round. which pieces of information can be gathered from these dot plots? (remember that lower swim times are faster.) choose all answers that apply: a: the swimmers had faster times on average in the final round. b: the times in the final round vary noticeably more than the times in the semifinal round. c: none of the above.

We just started the introduction into circles and i have no idea how to do this.

Precalculus question, image attached.