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.

What grade level is PS taught?

This standard is part of the PS curriculum in Virginia Standards of Learning - Mathematics.

PS: Probability and Statistics

Probability and Statistics

Print

Organizing, displaying, and analyzing data with appropriate statistical measures and graphs. Theoretical and experimental probability, bias identification in collection and analysis, and probability-based predictions. Bivariate data patterns and the limits of data-driven inference.

PS.DCData in Context PS.DSDescriptive Statistics PS.ISInferential Statistics PS.PProbability

Example Problems

A school chooses 3 randomly selected athletes from each of its sports teams to participate in a survey about athletics at the school.

What type of sample is this: simple random sample, stratified random sample, cluster random sample, or systematic random sample?

A fishery biologist recorded the length of trout, in centimeters, and their weight, in grams.
After plotting her results, the biologist noticed that the relationship between the two variables was fairly linear, so she used the data to calculate the following least squares regression equation for predicting weight, in grams, from length, in centimeters:

\hat{y} = -150 + 6x

What is the residual for a trout that is

32 \text{ cm}

long and weighs

55 \text{ grams}

?

Priya was testing

H_0: \mu = 20

versus

H_a: \mu < 20

with a sample of 12 observations. Her test statistic was

t = -2.228

. Assume that the conditions for inference were met.

What is the approximate P-value for Priya's test?
Round your answer to the nearest thousandth.

What is the critical value

z^{*}

for constructing a 90% confidence interval?

The parks department will repaint 5 of 50 trail markers. They number the markers

01-50

and use the random digit table printed below to choose a simple random sample.

Which markers are in the sample?

76054, 41328, 37961, 20584, 43310

1-on-1 AI tutoring aligned to PS. Instant help for students, real-time insights for teachers.

Used in classrooms by 100,000+ students at Baltimore County, Plano ISD, Deer Valley USD, KIPP, and districts nationwide.

Free for teachers, forever →