Is Goblins free for teachers?

Yes. Goblins offers a generous free tier that includes 1 live feedback assignment per week, insights on student mastery and replays, and the ability to upload your own content. The Max plan adds unlimited assignments, superadaptive mode, grade exports, standards growth reports, and SSO/LMS integration, with per-student pricing for schools and districts.

How does Goblins work?

Three simple steps: (1) Share an assignment from thousands of standards-aligned topics using a share code. (2) Students speak and draw their thinking naturally, and Goblins responds with Socratic questioning that sounds just like their teacher. (3) Teachers get real-time formative insights showing what students struggle with and suggestions to inform instruction.

Does Goblins prevent cheating?

Yes. Goblins uses a purpose-trained AI model that evaluates cheating signals in real time. It can detect when students are copying answers, using external tools inappropriately, or not genuinely working through problems. Copy-pasting answers is also blocked.

Can I use my own voice with Goblins?

Yes. Teachers can record their voice and take a selfie to create a custom 3D avatar in about 30 seconds. Students then hear help in their own teacher's voice and see a familiar face, making the experience more personal and effective.

What math levels does Goblins cover?

Goblins covers math from Grade 5 through AP Calculus, including thousands of standards-aligned topics. Teachers can also upload their own content for custom assignments at any level.

Is Goblins FERPA compliant?

Yes. Goblins is FERPA and state compliant. Student data privacy and security are a top priority.

Does Goblins support English Language Learners?

Yes. Goblins supports 30+ languages so teachers don't have to translate every worksheet. It is especially helpful for ELL students who need accessible math instruction in their native language.

PC.F.2

Find linear models by using median fit and least squares regression methods, making use of technology. Decide which among several linear models gives a better fit. Interpret the slope and intercept in terms of the original context.

Example Problems

An ornithologist wants to look at the relationship between the breadth of peregrine falcon eggs and the mass of the falcon chicks that hatch from them. The data show a linear pattern with the summary statistics shown below:

	mean	standard deviation
x = egg breadth (mm)	$\bar{x} = 41$	$s_x = 2.3$
y = chick's mass (g)	$\bar{y} = 33.6$	$s_y = 4.6$
		$r = 0.95$

Find the equation of the least-squares regression line for predicting the chick's mass from the breadth of the egg, in the form

\hat{y} = a + bx

.
Round your entries to the nearest hundredth.

A tutoring center director wants to look at the relationship between hours of tutoring and final grades. The data show a linear pattern with the summary statistics shown below:

	mean	standard deviation
$x$ = hours of tutoring	$\overline{x} = 8.5$	$s_x = 2$
$y$ = final grade (points)	$\overline{y} = 81$	$s_y = 10$
		$r = 0.89$

Find the equation of the least-squares regression line for predicting the final grade (points) from the hours of tutoring, in the form

\hat{y} = a + bx

.
Round your entries to the nearest hundredth.

An automotive journalist wants to look at the relationship between engine displacement and fuel economy. The data show a linear pattern with the summary statistics shown below:

	mean	standard deviation
$x$ = engine displacement (liters)	$\overline{x} = 3$	$s_x = 0.6$
$y$ = fuel economy (mpg)	$\overline{y} = 27$	$s_y = 6$
		$r = -0.94$

Find the equation of the least-squares regression line for predicting the fuel economy (mpg) from the engine displacement (liters), in the form

\hat{y} = a + bx

.
Round your entries to the nearest hundredth.

Khan Academy Resources

Equations of trend lines: Phone data Interpreting slope and y-intercept for linear models Interpreting slope of regression line Interpreting y-intercept in regression model

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