Is the calculation for how many D$\text{'}$s or F$\text{'}$s the first student received correct?

File: solution.m Line: $7$ Column: $27$

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

$ox$ Is the calculation for how many Ds on assignments the entire class received correct?

File: solution.m Line: $7$ Column: $27$

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

& Is the calculation for how many students received a D or F in their class final grade correct?

File: solution.m Line: $7$ Column: $27$

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

& Is the calculation of how many Ds or Fs did the students, on average, receive as a final grade correct?

File: solution.m Line: $7$ Column: $27$

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

& If the average number of final grade Ds or Fs exceeds $0\mathrm{.}15,$ was Answer$5$ set correctly? If this number does NOT exceed $0\mathrm{.}15,$ was Answer$5$ set correctly then?

File: solution.m Line: $7$ Column: $27$

Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

In Unit $3$ and $4,$ we talked a bit more about matrices, and introduced comparators with if$-$statements.

Logical Indexing Grades

My Solutions $>$

One of the things that instructors pay a lot of attention to$,$ is something called the DFW rate. This includes the number of Ds$,$ Fs$,$ and Ws $($withdrawals$)$ in a class. We all want to see this number as low as possible. Using the gradebook generated with the following randomization code, and assuming that each row is a student while each column is an assignment, answer the following questions.

grades $=$round$({60}^{**}$ rand $(50,15))+40$;

How many Ds or FS on assignments did the first student receive? Save this to Answer$1.($note$,$ use logical indexing for this, a comparator on an array$)$

How many Ds on assignments did the entire class receive? Save this to Answer$2$

How many students received a D or F in their class final grade? Save this to Answer$3.($note$,$ use the mean$()$ function to find the average grade for all students, assuming all assignments are equally weighted$)$

How many Ds or FS did the students, on average, receive as a final grade? Save this to Answer$4.($note$,$ you need to first figure out who received a D or F$,$ and then find what the fraction of entire class that this represents. Was it $0\mathrm{.}1$ students? That would be $1$ in $10.$ Was it $0\mathrm{.}2?$ Something else?$)$

If the average proportion of final grade Ds or Fs exceeds $0\mathrm{.}15,$ then assign Answer$5$ to $1,$ and otherwise set Answer$5$ to $0.$

Assume the following grade cutoffs:

$A$ is $90$

$B$ is $<mn\; id="EditorElement\_26213">9</mn><mn\; id="EditorElement\_26214">0</mn>$ and $80$

$C$ is $<mn\; id="EditorElement\_26166">8</mn><mn\; id="EditorElement\_26167">0</mn>$ and $70$

$D$ is $<mn\; id="EditorElement\_26119">7</mn><mn\; id="EditorElement\_26120">0</mn>$ and $60$

$F$ is $<mn\; id="EditorElement\_26072">6</mn><mn\; id="EditorElement\_26073">0</mn>$