How many can you get wrong or right on the National Boards and pass?

This paragraph from Prentice Hall's - Complete Review of Dental Hygiene Page 12 says:

A score of 75 is used as a passing score for the National Board Examination. This is not a raw score.
This means that a candidate does not need to correctly answer 75% of all the questions to pass the
examination. The number of correct answers required is determined by the conversion scale. An
average raw score of approximately 65% converts to a standard score of 80 to an 85. Typically,less
than 10% of all first-time candidates score below a 75. Over 90% pass!

Does that make you feel better? Well after I read that I immediately felt relieved after calculating the math that was presented here.
Let me show you how I worked it out.

If a raw score of 65% converts to an 80-85% and we need to make a least a 75% to pass we can conclude that:

Just to be safe we will go ahead and round these 2 numbers up to a whole # percent.

So based on this you need to answer 58-61% of the questions correct to give you a standard score of a 75 on the Dental Hygiene National Board! Feel better yet?

Now take this and apply it to the 350 question exam.

Morning session has 200 questions

To answer 58-61% correct out of 200 that means you have to answer 116-122 correct...which in turn means you can get 78-84 questions incorrect on the AM portion to equal the boards standard score of 75%

The afternoon session has 15 case studies with 150 questions.

If we apply the same principle then to answer 58-61% correct out of 150 that means you have to answer 87-92 correct...which in turn means you can get 58-68 questions incorrect on the PM portion to equal the boards standard score of 75%

Now lets combine the AM and PM sessions to give us an overall estimate

You have to get at least 203 - 214 correct to give you a standard score of 75!

That means you can get 136-152 questions incorrect on the entire national board to have at least a 75 score on the National Boards!

So how do you feel now? I know that this may be the math of the exam but in no way are we striving to get at least 214 questions correct! We want 100%, right? That's right! Please also take into consideration that we do not know what questions the board committee will throw out! Could they throw out 10 questions? 20? 30? We don't know! And what happens if we just happened to get a majority of the questions correct that they threw out? That's why each and everyone of us are striving for that big 100% and that beautiful "RDH" beside our name! We can do it! We WILL do it!

These calculations are also based on answering all 350 questions and not leaving any blank!