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.

S-ID.6.c

Fit a linear function for a scatter plot that suggests a linear association.

Example Problems

Zara studied the age (in years) and resale value (in thousand dollars) of a random sample of 40 used cars. Here is computer output on the sample data:

Regression: resale value vs. age

Predictor	Coef	SE Coef
Constant	18.7	0.9
Age	-1.85	0.31

S = 2.62

R\text{-sq} = 68.1\%

Assume that all conditions for inference have been met.

Write the expression for the test statistic for testing the null hypothesis that the population slope in this setting is

0

Leona collected data on the battery life (in hours) and price (in dollars) of a random sample of mobile phones. Here is computer output from a least-squares regression analysis on her sample:

Predictor	Coef	SE Coef
Constant	191.312	94.318
Battery life	6.556	3.788

S = 199.5 \quad R\text{-sq} = 3.1\%

Assume that all conditions for inference have been met.

Write the expression for the test statistic for testing the null hypothesis that the population slope in this setting is 0.

Isabella is studying the relationship between daily study hours and exam score. She records data for a random sample of 22 students. Here is computer output from a least-squares regression analysis on her sample:

Predictor	Coef	SE Coef	T	P
Constant	52.30	5.05	10.36	0.00
Study hours	4.52	1.05	4.30	0.00

S = 8.80 \quad R\text{-sq} = 58.6\%

Assume that all conditions for inference have been met.

Write the expression for a 99% confidence interval for the slope of the least squares regression line.

Khan Academy Resources

Introduction to residuals and least-squares regression

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