What is the probability that, if she takes 4.5 mg, her reaction time will be more than 7ms? (data in question)?

Can someone help me with my adv. stat problem please? You find seven friends, and agree to give them each a predetermined amount of a new drug partyobenzene. Half an hour later, you measure their reaction time and record it in a table, here is the data below. Amount (mg), Reaction Time (ms): 1mg,3ms 2mg,5ms 3mg,4ms 4mg,6ms 5mg,7ms 6mg,7ms 7mg,10ms You have another friend who is going bowling tomorrow, but really wants to try 4.5 mg of partyobenzene. She decides that if her reaction time is 7ms or less, she'll bowl fine. What is the probability that, if she takes 4.5 mg, her reaction time will be more that 7ms? Thanks so much for your help!!!

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Least squares regression gives an equation of $y=1.0357x+1.8571$ with standard deviation 2.10629. 4.5mg would give an expected value of 6.51775ms.
$\frac{7-6.51775}{2.10629}=0.228957$ standard deviations.
$\frac{1-erf\frac{0.228957}{\sqrt2}}2=0.41$